# Source code for rdflib.term

    """
    This module defines the different types of terms. Terms are the kinds of
    objects that can appear in a quoted/asserted triple. This includes those
    that are core to RDF:

    * :class:`Blank Nodes <rdflib.term.BNode>`
    * :class:`URI References <rdflib.term.URIRef>`
    * :class:`Literals <rdflib.term.Literal>` (which consist of a literal value,datatype and language tag)

    Those that extend the RDF model into N3:

    * :class:`Formulae <rdflib.graph.QuotedGraph>`
    * :class:`Universal Quantifications (Variables) <rdflib.term.Variable>`

    And those that are primarily for matching against 'Nodes' in the
    underlying Graph:

    * REGEX Expressions
    * Date Ranges
    * Numerical Ranges

    """

    from __future__ import annotations

    import abc
    import re
    from fractions import Fraction

    __all__ = [
        "bind",
        "_is_valid_uri",
        "Node",
        "IdentifiedNode",
        "Identifier",
        "URIRef",
        "BNode",
        "Literal",
        "Variable",
    ]
    import logging
    import math
    import warnings
    import xml.dom.minidom
    from base64 import b64decode, b64encode
    from binascii import hexlify, unhexlify
    from collections import defaultdict
    from datetime import date, datetime, time, timedelta
    from decimal import Decimal
    from re import compile, sub
    from types import GeneratorType
    from typing import (
        TYPE_CHECKING,
        Any,
        Callable,
        Dict,
        Generator,
        List,
        Optional,
        Tuple,
        Type,
        TypeVar,
        Union,
    )
    from urllib.parse import urldefrag, urljoin, urlparse
    from uuid import uuid4

    import rdflib
    import rdflib.util
    from rdflib.compat import long_type

    from .xsd_datetime import (  # type: ignore[attr-defined]
        Duration,
        duration_isoformat,
        parse_datetime,
        parse_time,
        parse_xsd_date,
        parse_xsd_duration,
        parse_xsd_gyear,
        parse_xsd_gyearmonth,
    )

    if TYPE_CHECKING:
        from .namespace import NamespaceManager
        from .paths import AlternativePath, InvPath, NegatedPath, Path, SequencePath

    _HAS_HTML5RDF = False

    try:
        import html5rdf

        _HAS_HTML5RDF = True
    except ImportError:
        html5rdf = None

    _SKOLEM_DEFAULT_AUTHORITY = "https://rdflib.github.io"

    logger = logging.getLogger(__name__)
    skolem_genid = "/.well-known/genid/"
    rdflib_skolem_genid = "/.well-known/genid/rdflib/"
    skolems: Dict[str, BNode] = {}

    _invalid_uri_chars = '<>" {}|\\^`'

    def _is_valid_uri(uri: str) -> bool:
        for c in _invalid_uri_chars:
            if c in uri:
                return False
        return True

    _lang_tag_regex = compile("^[a-zA-Z]+(?:-[a-zA-Z0-9]+)*$")

    def _is_valid_langtag(tag: str) -> bool:
        return bool(_lang_tag_regex.match(tag))

    def _is_valid_unicode(value: Union[str, bytes]) -> bool:
        """
        Verify that the provided value can be converted into a Python
        unicode object.
        """
        if isinstance(value, bytes):
            coding_func, param = getattr(value, "decode"), "utf-8"
        else:
            coding_func, param = str, value

        # try to convert value into unicode
        try:
            coding_func(param)
        except UnicodeError:
            return False
        return True

    class Node(abc.ABC):
        """
        A Node in the Graph.
        """

        __slots__ = ()

        @abc.abstractmethod
        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str: ...

    class Identifier(Node, str):  # allow Identifiers to be Nodes in the Graph
        """
        See http://www.w3.org/2002/07/rdf-identifer-terminology/
        regarding choice of terminology.
        """

        __slots__ = ()

        def __new__(cls, value: str) -> Identifier:
            return str.__new__(cls, value)

        def eq(self, other: Any) -> bool:
            """A "semantic"/interpreted equality function,
            by default, same as __eq__"""
            return self.__eq__(other)

        def neq(self, other: Any) -> bool:
            """A "semantic"/interpreted not equal function,
            by default, same as __ne__"""
            return self.__ne__(other)

        def __ne__(self, other: Any) -> bool:
            return not self.__eq__(other)

        def __eq__(self, other: Any) -> bool:
            """
            Equality for Nodes.

            >>> BNode("foo")==None
            False
            >>> BNode("foo")==URIRef("foo")
            False
            >>> URIRef("foo")==BNode("foo")
            False
            >>> BNode("foo")!=URIRef("foo")
            True
            >>> URIRef("foo")!=BNode("foo")
            True
            >>> Variable('a')!=URIRef('a')
            True
            >>> Variable('a')!=Variable('a')
            False
            """

            if type(self) is type(other):
                return str(self) == str(other)
            else:
                return False

        def __gt__(self, other: Any) -> bool:
            """
            This implements ordering for Nodes,

            This tries to implement this:
            http://www.w3.org/TR/sparql11-query/#modOrderBy

            Variables are not included in the SPARQL list, but
            they are greater than BNodes and smaller than everything else

            """
            if other is None:
                return True  # everything bigger than None
            elif type(self) is type(other):
                return str(self) > str(other)
            elif isinstance(other, Node):
                return _ORDERING[type(self)] > _ORDERING[type(other)]

            return NotImplemented

        def __lt__(self, other: Any) -> bool:
            if other is None:
                return False  # Nothing is less than None
            elif type(self) is type(other):
                return str(self) < str(other)
            elif isinstance(other, Node):
                return _ORDERING[type(self)] < _ORDERING[type(other)]

            return NotImplemented

        def __le__(self, other: Any) -> bool:
            r = self.__lt__(other)
            if r:
                return True
            return self == other

        def __ge__(self, other: Any) -> bool:
            r = self.__gt__(other)
            if r:
                return True
            return self == other

        # type error: Argument 1 of "startswith" is incompatible with supertype "str"; supertype defines the argument type as "Union[str, Tuple[str, ...]]"
        # FIXME: this does not accommodate prefix of type Tuple[str, ...] which is a
        # valid for str.startswith

        def startswith(self, prefix: str, start=..., end=...) -> bool:  # type: ignore[override] # FIXME
            return str(self).startswith(str(prefix))

        # use parent's hash for efficiency reasons
        # clashes of 'foo', URIRef('foo') and Literal('foo') are typically so rare
        # that they don't justify additional overhead. Notice that even in case of
        # clash __eq__ is still the fallback and very quick in those cases.
        __hash__ = str.__hash__

    class IdentifiedNode(Identifier):
        """
        An abstract class, primarily defined to identify Nodes that are not Literals.

        The name "Identified Node" is not explicitly defined in the RDF specification, but can be drawn from this section: https://www.w3.org/TR/rdf-concepts/#section-URI-Vocabulary
        """

        __slots__ = ()

        def __getnewargs__(self) -> Tuple[str]:
            return (str(self),)

        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str:
            raise NotImplementedError()

        def toPython(self) -> str:  # noqa: N802
            return str(self)

    class URIRef(IdentifiedNode):
        """
        RDF 1.1's IRI Section https://www.w3.org/TR/rdf11-concepts/#section-IRIs

        .. note:: Documentation on RDF outside of RDFLib uses the term IRI or URI whereas this class is called URIRef. This is because it was made when the first version of the RDF specification was current, and it used the term *URIRef*, see `RDF 1.0 URIRef <http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref>`_

        An IRI (Internationalized Resource Identifier) within an RDF graph is a Unicode string that conforms to the syntax defined in RFC 3987.

        IRIs in the RDF abstract syntax MUST be absolute, and MAY contain a fragment identifier.

        IRIs are a generalization of URIs [RFC3986] that permits a wider range of Unicode characters.
        """

        __slots__ = ()

        __or__: Callable[[URIRef, Union[URIRef, Path]], AlternativePath]
        __invert__: Callable[[URIRef], InvPath]
        __neg__: Callable[[URIRef], NegatedPath]
        __truediv__: Callable[[URIRef, Union[URIRef, Path]], SequencePath]

        def __new__(cls, value: str, base: Optional[str] = None) -> URIRef:
            if base is not None:
                ends_in_hash = value.endswith("#")
                # type error: Argument "allow_fragments" to "urljoin" has incompatible type "int"; expected "bool"
                value = urljoin(base, value, allow_fragments=1)  # type: ignore[arg-type]
                if ends_in_hash:
                    if not value.endswith("#"):
                        value += "#"

            if not _is_valid_uri(value):
                logger.warning(
                    f"{value} does not look like a valid URI, trying to serialize this will break."
                )

            try:
                rt = str.__new__(cls, value)
            except UnicodeDecodeError:
                # type error: No overload variant of "__new__" of "str" matches argument types "Type[URIRef]", "str", "str"
                rt = str.__new__(cls, value, "utf-8")  # type: ignore[call-overload]
            return rt

        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str:
            """
            This will do a limited check for valid URIs,
            essentially just making sure that the string includes no illegal
            characters (``<, >, ", {, }, |, \\, `, ^``)

            :param namespace_manager: if not None, will be used to make up
                 a prefixed name
            """

            if not _is_valid_uri(self):
                raise Exception(
                    f'"{self}" does not look like a valid URI, I cannot serialize this as N3/Turtle. Perhaps you wanted to urlencode it?'
                )

            if namespace_manager:
                return namespace_manager.normalizeUri(self)
            else:
                return f"<{self}>"

        def defrag(self) -> URIRef:
            if "#" in self:
                url, frag = urldefrag(self)
                return URIRef(url)
            else:
                return self

        @property
        def fragment(self) -> str:
            """
            Return the URL Fragment

            >>> URIRef("http://example.com/some/path/#some-fragment").fragment
            'some-fragment'
            >>> URIRef("http://example.com/some/path/").fragment
            ''
            """
            return urlparse(self).fragment

        def __reduce__(self) -> Tuple[Type[URIRef], Tuple[str]]:
            return (URIRef, (str(self),))

        def __repr__(self) -> str:
            if self.__class__ is URIRef:
                clsName = "rdflib.term.URIRef"  # noqa: N806
            else:
                clsName = self.__class__.__name__  # noqa: N806

            return f"{clsName}({str.__repr__(self)})"

        def __add__(self, other) -> URIRef:
            return self.__class__(str(self) + other)

        def __radd__(self, other) -> URIRef:
            return self.__class__(other + str(self))

        def __mod__(self, other) -> URIRef:
            return self.__class__(str(self) % other)

        def de_skolemize(self) -> BNode:
            """Create a Blank Node from a skolem URI, in accordance
            with http://www.w3.org/TR/rdf11-concepts/#section-skolemization.
            This function accepts only rdflib type skolemization, to provide
            a round-tripping within the system.

            .. versionadded:: 4.0
            """
            if isinstance(self, RDFLibGenid):
                parsed_uri = urlparse(f"{self}")
                return BNode(value=parsed_uri.path[len(rdflib_skolem_genid) :])
            elif isinstance(self, Genid):
                bnode_id = f"{self}"
                if bnode_id in skolems:
                    return skolems[bnode_id]
                else:
                    retval = BNode()
                    skolems[bnode_id] = retval
                    return retval
            else:
                raise Exception(f"<{self}> is not a skolem URI")

    class Genid(URIRef):
        __slots__ = ()

        @staticmethod
        def _is_external_skolem(uri: Any) -> bool:
            if not isinstance(uri, str):
                uri = str(uri)
            parsed_uri = urlparse(uri)
            gen_id = parsed_uri.path.rfind(skolem_genid)
            if gen_id != 0:
                return False
            return True

    class RDFLibGenid(Genid):
        __slots__ = ()

        @staticmethod
        def _is_rdflib_skolem(uri: Any) -> bool:
            if not isinstance(uri, str):
                uri = str(uri)
            parsed_uri = urlparse(uri)
            if (
                parsed_uri.params != ""
                or parsed_uri.query != ""
                or parsed_uri.fragment != ""
            ):
                return False
            gen_id = parsed_uri.path.rfind(rdflib_skolem_genid)
            if gen_id != 0:
                return False
            return True

    def _unique_id() -> str:
        # Used to read: """Create a (hopefully) unique prefix"""
        # now retained merely to leave internal API unchanged.
        # From BNode.__new__() below ...
        #
        # acceptable bnode value range for RDF/XML needs to be
        # something that can be serialzed as a nodeID for N3
        #
        # BNode identifiers must be valid NCNames" _:[A-Za-z][A-Za-z0-9]*
        # http://www.w3.org/TR/2004/REC-rdf-testcases-20040210/#nodeID
        return "N"  # ensure that id starts with a letter

    class BNode(IdentifiedNode):
        """
        RDF 1.1's Blank Nodes Section: https://www.w3.org/TR/rdf11-concepts/#section-blank-nodes

        Blank Nodes are local identifiers for unnamed nodes in RDF graphs that are used in
        some concrete RDF syntaxes or RDF store implementations. They are always locally
        scoped to the file or RDF store, and are not persistent or portable identifiers for
        blank nodes. The identifiers for Blank Nodes are not part of the RDF abstract
        syntax, but are entirely dependent on particular concrete syntax or implementation
        (such as Turtle, JSON-LD).

        ---

        RDFLib's ``BNode`` class makes unique IDs for all the Blank Nodes in a Graph but you
        should *never* expect, or reply on, BNodes' IDs to match across graphs, or even for
        multiple copies of the same graph, if they are regenerated from some non-RDFLib
        source, such as loading from RDF data.
        """

        __slots__ = ()

        def __new__(
            cls,
            value: Optional[str] = None,
            _sn_gen: Optional[Union[Callable[[], str], Generator]] = None,
            _prefix: str = _unique_id(),
        ) -> BNode:
            """
            # only store implementations should pass in a value
            """
            if value is None:
                # so that BNode values do not collide with ones created with
                # a different instance of this module at some other time.
                if _sn_gen is not None:
                    if callable(_sn_gen):
                        sn_result: Union[str, Generator] = _sn_gen()
                    else:
                        sn_result = _sn_gen
                    if isinstance(sn_result, GeneratorType):
                        node_id = next(sn_result)
                    else:
                        node_id = sn_result
                else:
                    node_id = uuid4().hex
                # note, for two (and only two) string variables,
                # concat with + is faster than f"{x}{y}"
                value = _prefix + f"{node_id}"
            else:
                # TODO: check that value falls within acceptable bnode value range
                # for RDF/XML needs to be something that can be serialized
                # as a nodeID for N3 ??  Unless we require these
                # constraints be enforced elsewhere?
                pass  # assert is_ncname(str(value)), "BNode identifiers
                # must be valid NCNames" _:[A-Za-z][A-Za-z0-9]*
                # http://www.w3.org/TR/2004/REC-rdf-testcases-20040210/#nodeID
            # type error: Incompatible return value type (got "Identifier", expected "BNode")
            return Identifier.__new__(cls, value)  # type: ignore[return-value]

        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str:
            # note - for two strings, concat with + is faster than f"{x}{y}"
            return "_:" + self

        def __reduce__(self) -> Tuple[Type[BNode], Tuple[str]]:
            return (BNode, (str(self),))

        def __repr__(self) -> str:
            if self.__class__ is BNode:
                clsName = "rdflib.term.BNode"  # noqa: N806
            else:
                clsName = self.__class__.__name__  # noqa: N806
            return f"{clsName}({str.__repr__(self)})"

        def skolemize(
            self, authority: Optional[str] = None, basepath: Optional[str] = None
        ) -> URIRef:
            """Create a URIRef "skolem" representation of the BNode, in accordance
            with http://www.w3.org/TR/rdf11-concepts/#section-skolemization

            .. versionadded:: 4.0
            """
            if authority is None:
                authority = _SKOLEM_DEFAULT_AUTHORITY
            if basepath is None:
                basepath = rdflib_skolem_genid
            skolem = basepath + str(self)
            return URIRef(urljoin(authority, skolem))

    class Literal(Identifier):
        """

        RDF 1.1's Literals Section: http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal

        Literals are used for values such as strings, numbers, and dates.

        A literal in an RDF graph consists of two or three elements:

        * a lexical form, being a Unicode string, which SHOULD be in Normal Form C
        * a datatype IRI, being an IRI identifying a datatype that determines how the lexical form maps to a literal value, and
        * if and only if the datatype IRI is ``http://www.w3.org/1999/02/22-rdf-syntax-ns#langString``, a non-empty language tag. The language tag MUST be well-formed according to section 2.2.9 of `Tags for identifying languages <http://tools.ietf.org/html/bcp47>`_.

        A literal is a language-tagged string if the third element is present. Lexical representations of language tags MAY be converted to lower case. The value space of language tags is always in lower case.

        ---

        For valid XSD datatypes, the lexical form is optionally normalized
        at construction time. Default behaviour is set by rdflib.NORMALIZE_LITERALS
        and can be overridden by the normalize parameter to __new__

        Equality and hashing of Literals are done based on the lexical form, i.e.:

        >>> from rdflib.namespace import XSD

        >>> Literal('01') != Literal('1')  # clear - strings differ
        True

        but with data-type they get normalized:

        >>> Literal('01', datatype=XSD.integer) != Literal('1', datatype=XSD.integer)
        False

        unless disabled:

        >>> Literal('01', datatype=XSD.integer, normalize=False) != Literal('1', datatype=XSD.integer)
        True

        Value based comparison is possible:

        >>> Literal('01', datatype=XSD.integer).eq(Literal('1', datatype=XSD.float))
        True

        The eq method also provides limited support for basic python types:

        >>> Literal(1).eq(1) # fine - int compatible with xsd:integer
        True
        >>> Literal('a').eq('b') # fine - str compatible with plain-lit
        False
        >>> Literal('a', datatype=XSD.string).eq('a') # fine - str compatible with xsd:string
        True
        >>> Literal('a').eq(1) # not fine, int incompatible with plain-lit
        NotImplemented

        Greater-than/less-than ordering comparisons are also done in value
        space, when compatible datatypes are used.  Incompatible datatypes
        are ordered by DT, or by lang-tag.  For other nodes the ordering
        is None < BNode < URIRef < Literal

        Any comparison with non-rdflib Node are "NotImplemented"
        In PY3 this is an error.

        >>> from rdflib import Literal, XSD
        >>> lit2006 = Literal('2006-01-01',datatype=XSD.date)
        >>> lit2006.toPython()
        datetime.date(2006, 1, 1)
        >>> lit2006 < Literal('2007-01-01',datatype=XSD.date)
        True
        >>> Literal(datetime.utcnow()).datatype
        rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#dateTime')
        >>> Literal(1) > Literal(2) # by value
        False
        >>> Literal(1) > Literal(2.0) # by value
        False
        >>> Literal('1') > Literal(1) # by DT
        True
        >>> Literal('1') < Literal('1') # by lexical form
        False
        >>> Literal('a', lang='en') > Literal('a', lang='fr') # by lang-tag
        False
        >>> Literal(1) > URIRef('foo') # by node-type
        True

        The > < operators will eat this NotImplemented and throw a TypeError (py3k):

        >>> Literal(1).__gt__(2.0)
        NotImplemented

        """

        _value: Any
        _language: Optional[str]
        # NOTE: _datatype should maybe be of type URIRef, and not optional.
        _datatype: Optional[URIRef]
        _ill_typed: Optional[bool]
        __slots__ = ("_language", "_datatype", "_value", "_ill_typed")

        def __new__(
            cls,
            lexical_or_value: Any,
            lang: Optional[str] = None,
            datatype: Optional[str] = None,
            normalize: Optional[bool] = None,
        ) -> Literal:
            if lang == "":
                lang = None  # no empty lang-tags in RDF

            normalize = normalize if normalize is not None else rdflib.NORMALIZE_LITERALS

            if lang is not None and datatype is not None:
                raise TypeError(
                    "A Literal can only have one of lang or datatype, "
                    "per http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal"
                )

            if lang is not None and not _is_valid_langtag(lang):
                raise ValueError(f"'{str(lang)}' is not a valid language tag!")

            if datatype is not None:
                datatype = URIRef(datatype)

            value = None
            ill_typed: Optional[bool] = None
            if isinstance(lexical_or_value, Literal):
                # create from another Literal instance

                lang = lang or lexical_or_value.language
                if datatype is not None:
                    # override datatype
                    value = _castLexicalToPython(lexical_or_value, datatype)
                else:
                    datatype = lexical_or_value.datatype
                    value = lexical_or_value.value

            elif isinstance(lexical_or_value, str) or isinstance(lexical_or_value, bytes):
                # passed a string
                # try parsing lexical form of datatyped literal
                value = _castLexicalToPython(lexical_or_value, datatype)
                if datatype is not None and datatype in _toPythonMapping:
                    # datatype is a recognized datatype IRI:
                    # https://www.w3.org/TR/rdf11-concepts/#dfn-recognized-datatype-iris
                    dt_uri: URIRef = URIRef(datatype)
                    checker = _check_well_formed_types.get(dt_uri, _well_formed_by_value)
                    well_formed = checker(lexical_or_value, value)
                    ill_typed = ill_typed or (not well_formed)
                if value is not None and normalize:
                    _value, _datatype = _castPythonToLiteral(value, datatype)
                    if _value is not None and _is_valid_unicode(_value):
                        lexical_or_value = _value

            else:
                # passed some python object
                value = lexical_or_value
                _value, _datatype = _castPythonToLiteral(lexical_or_value, datatype)

                _datatype = None if _datatype is None else URIRef(_datatype)

                datatype = rdflib.util._coalesce(datatype, _datatype)
                if _value is not None:
                    lexical_or_value = _value
                if datatype is not None:
                    lang = None

            if isinstance(lexical_or_value, bytes):
                lexical_or_value = lexical_or_value.decode("utf-8")

            if datatype in (_XSD_NORMALISED_STRING, _XSD_TOKEN):
                lexical_or_value = _normalise_XSD_STRING(lexical_or_value)

            if datatype in (_XSD_TOKEN,):
                lexical_or_value = _strip_and_collapse_whitespace(lexical_or_value)

            try:
                inst: Literal = str.__new__(cls, lexical_or_value)
            except UnicodeDecodeError:
                inst = str.__new__(cls, lexical_or_value, "utf-8")

            inst._language = lang
            inst._datatype = datatype
            inst._value = value
            inst._ill_typed = ill_typed

            return inst

        def normalize(self) -> Literal:
            """
            Returns a new literal with a normalised lexical representation
            of this literal
            >>> from rdflib import XSD
            >>> Literal("01", datatype=XSD.integer, normalize=False).normalize()
            rdflib.term.Literal('1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            Illegal lexical forms for the datatype given are simply passed on
            >>> Literal("a", datatype=XSD.integer, normalize=False)
            rdflib.term.Literal('a', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            """

            if self.value is not None:
                return Literal(self.value, datatype=self.datatype, lang=self.language)
            else:
                return self

        @property
        def ill_typed(self) -> Optional[bool]:
            """
            For `recognized datatype IRIs
            <https://www.w3.org/TR/rdf11-concepts/#dfn-recognized-datatype-iris>`_,
            this value will be `True` if the literal is ill formed, otherwise it
            will be `False`. `Literal.value` (i.e. the `literal value <https://www.w3.org/TR/rdf11-concepts/#dfn-literal-value>`_) should always be defined if this property is `False`, but should not be considered reliable if this property is `True`.

            If the literal's datatype is `None` or not in the set of `recognized datatype IRIs
            <https://www.w3.org/TR/rdf11-concepts/#dfn-recognized-datatype-iris>`_ this value will be `None`.
            """
            return self._ill_typed

        @property
        def value(self) -> Any:
            return self._value

        @property
        def language(self) -> Optional[str]:
            return self._language

        @property
        def datatype(self) -> Optional[URIRef]:
            return self._datatype

        def __reduce__(
            self,
        ) -> Tuple[Type[Literal], Tuple[str, Union[str, None], Union[str, None]]]:
            return (
                Literal,
                (str(self), self.language, self.datatype),
            )

        def __getstate__(self) -> Tuple[None, Dict[str, Union[str, None]]]:
            return (None, dict(language=self.language, datatype=self.datatype))

        def __setstate__(self, arg: Tuple[Any, Dict[str, Any]]) -> None:
            _, d = arg
            self._language = d["language"]
            self._datatype = d["datatype"]

        def __add__(self, val: Any) -> Literal:
            """
            >>> from rdflib.namespace import XSD
            >>> Literal(1) + 1
            rdflib.term.Literal('2', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))
            >>> Literal("1") + "1"
            rdflib.term.Literal('11')

            # Handling dateTime/date/time based operations in Literals
            >>> a = Literal('2006-01-01T20:50:00', datatype=XSD.dateTime)
            >>> b = Literal('P31D', datatype=XSD.duration)
            >>> (a + b)
            rdflib.term.Literal('2006-02-01T20:50:00', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#dateTime'))
            >>> from rdflib.namespace import XSD
            >>> a = Literal('2006-07-01T20:52:00', datatype=XSD.dateTime)
            >>> b = Literal('P122DT15H58M', datatype=XSD.duration)
            >>> (a + b)
            rdflib.term.Literal('2006-11-01T12:50:00', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#dateTime'))
            """

            # if no val is supplied, return this Literal
            if val is None:
                return self

            # convert the val to a Literal, if it isn't already one
            if not isinstance(val, Literal):
                val = Literal(val)

            # if self is datetime based and value is duration
            if (
                self.datatype in (_XSD_DATETIME, _XSD_DATE)
                and val.datatype in _TIME_DELTA_TYPES
            ):
                date1: Union[datetime, date] = self.toPython()
                duration: Union[Duration, timedelta] = val.toPython()
                difference = date1 + duration
                return Literal(difference, datatype=self.datatype)

            # if self is time based and value is duration
            elif self.datatype == _XSD_TIME and val.datatype in _TIME_DELTA_TYPES:
                selfv: time = self.toPython()
                valv: Union[Duration, timedelta] = val.toPython()
                sdt = datetime.combine(date(2000, 1, 1), selfv) + valv
                return Literal(sdt.time(), datatype=self.datatype)

            # if self is datetime based and value is not or vice versa
            elif (
                (
                    self.datatype in _ALL_DATE_AND_TIME_TYPES
                    and val.datatype not in _ALL_DATE_AND_TIME_TYPES
                )
                or (
                    self.datatype not in _ALL_DATE_AND_TIME_TYPES
                    and val.datatype in _ALL_DATE_AND_TIME_TYPES
                )
                or (
                    self.datatype in _TIME_DELTA_TYPES
                    and (
                        (val.datatype not in _TIME_DELTA_TYPES)
                        or (self.datatype != val.datatype)
                    )
                )
            ):
                raise TypeError(
                    f"Cannot add a Literal of datatype {str(val.datatype)} to a Literal of datatype {str(self.datatype)}"
                )

            # if the datatypes are the same, just add the Python values and convert back
            if self.datatype == val.datatype:
                return Literal(
                    self.toPython() + val.toPython(), self.language, datatype=self.datatype
                )
            # if the datatypes are not the same but are both numeric, add the Python values and strip off decimal junk
            # (i.e. tiny numbers (more than 17 decimal places) and trailing zeros) and return as a decimal
            elif (
                self.datatype in _NUMERIC_LITERAL_TYPES
                and val.datatype in _NUMERIC_LITERAL_TYPES
            ):
                return Literal(
                    Decimal(
                        f"{round(Decimal(self.toPython()) + Decimal(val.toPython()), 15):f}".rstrip(
                            "0"
                        ).rstrip(
                            "."
                        )
                    ),
                    datatype=_XSD_DECIMAL,
                )
            # in all other cases, perform string concatenation
            else:
                try:
                    s = str.__add__(self, val)
                except TypeError:
                    s = str(self.value) + str(val)

                # if the original datatype is string-like, use that
                if self.datatype in _STRING_LITERAL_TYPES:
                    new_datatype = self.datatype
                # if not, use string
                else:
                    new_datatype = _XSD_STRING

                return Literal(s, self.language, datatype=new_datatype)

        def __sub__(self, val: Any) -> Literal:
            """
            >>> from rdflib.namespace import XSD
            >>> Literal(2) - 1
            rdflib.term.Literal('1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))
            >>> Literal(1.1) - 1.0
            rdflib.term.Literal('0.10000000000000009', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#double'))
            >>> Literal(1.1) - 1
            rdflib.term.Literal('0.1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#decimal'))
            >>> Literal(1.1, datatype=XSD.float) - Literal(1.0, datatype=XSD.float)
            rdflib.term.Literal('0.10000000000000009', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#float'))
            >>> Literal("1.1") - 1.0 # doctest: +IGNORE_EXCEPTION_DETAIL
            Traceback (most recent call last):
            ...
            TypeError: Not a number; rdflib.term.Literal('1.1')
            >>> Literal(1.1, datatype=XSD.integer) - Literal(1.0, datatype=XSD.integer)
            rdflib.term.Literal('0.10000000000000009', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            # Handling dateTime/date/time based operations in Literals
            >>> a = Literal('2006-01-01T20:50:00', datatype=XSD.dateTime)
            >>> b = Literal('2006-02-01T20:50:00', datatype=XSD.dateTime)
            >>> (b - a)
            rdflib.term.Literal('P31D', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#duration'))
            >>> from rdflib.namespace import XSD
            >>> a = Literal('2006-07-01T20:52:00', datatype=XSD.dateTime)
            >>> b = Literal('2006-11-01T12:50:00', datatype=XSD.dateTime)
            >>> (a - b)
            rdflib.term.Literal('-P122DT15H58M', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#duration'))
            >>> (b - a)
            rdflib.term.Literal('P122DT15H58M', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#duration'))

            """
            # if no val is supplied, return this Literal
            if val is None:
                return self

            # convert the val to a Literal, if it isn't already one
            if not isinstance(val, Literal):
                val = Literal(val)

            if not getattr(self, "datatype"):
                raise TypeError(
                    "Minuend Literal must have Numeric, Date, Datetime or Time datatype."
                )
            elif not getattr(val, "datatype"):
                raise TypeError(
                    "Subtrahend Literal must have Numeric, Date, Datetime or Time datatype."
                )

            if (
                self.datatype in (_XSD_DATETIME, _XSD_DATE)
                and val.datatype in _TIME_DELTA_TYPES
            ):
                date1: Union[datetime, date] = self.toPython()
                duration: Union[Duration, timedelta] = val.toPython()
                difference = date1 - duration
                return Literal(difference, datatype=self.datatype)

            # if self is time based and value is duration
            elif self.datatype == _XSD_TIME and val.datatype in _TIME_DELTA_TYPES:
                selfv: time = self.toPython()
                valv: Union[Duration, timedelta] = val.toPython()
                sdt = datetime.combine(date(2000, 1, 1), selfv) - valv
                return Literal(sdt.time(), datatype=self.datatype)

            # if the datatypes are the same, just subtract the Python values and convert back
            if self.datatype == val.datatype:
                if self.datatype == _XSD_TIME:
                    sdt = datetime.combine(date.today(), self.toPython())
                    vdt = datetime.combine(date.today(), val.toPython())
                    return Literal(sdt - vdt, datatype=_XSD_DURATION)
                else:
                    return Literal(
                        self.toPython() - val.toPython(),
                        self.language,
                        datatype=(
                            _XSD_DURATION
                            if self.datatype in (_XSD_DATETIME, _XSD_DATE, _XSD_TIME)
                            else self.datatype
                        ),
                    )

            # if the datatypes are not the same but are both numeric, subtract the Python values and strip off decimal junk
            # (i.e. tiny numbers (more than 17 decimal places) and trailing zeros) and return as a decimal
            elif (
                self.datatype in _NUMERIC_LITERAL_TYPES
                and val.datatype in _NUMERIC_LITERAL_TYPES
            ):
                return Literal(
                    Decimal(
                        f"{round(Decimal(self.toPython()) - Decimal(val.toPython()), 15):f}".rstrip(
                            "0"
                        ).rstrip(
                            "."
                        )
                    ),
                    datatype=_XSD_DECIMAL,
                )
            # in all other cases, perform string concatenation
            else:
                raise TypeError(
                    f"Cannot subtract a Literal of datatype {str(val.datatype)} from a Literal of datatype {str(self.datatype)}"
                )

        def __bool__(self) -> bool:
            """
            Is the Literal "True"
            This is used for if statements, bool(literal), etc.
            """
            if self.value is not None:
                return bool(self.value)
            return len(self) != 0

        def __neg__(self) -> Literal:
            """
            >>> (- Literal(1))
            rdflib.term.Literal('-1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))
            >>> (- Literal(10.5))
            rdflib.term.Literal('-10.5', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#double'))
            >>> from rdflib.namespace import XSD
            >>> (- Literal("1", datatype=XSD.integer))
            rdflib.term.Literal('-1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            >>> (- Literal("1"))
            Traceback (most recent call last):
              File "<stdin>", line 1, in <module>
            TypeError: Not a number; rdflib.term.Literal('1')
            >>>
            """

            if isinstance(self.value, (int, long_type, float)):
                return Literal(self.value.__neg__())
            else:
                raise TypeError(f"Not a number; {self!r}")

        def __pos__(self) -> Literal:
            """
            >>> (+ Literal(1))
            rdflib.term.Literal('1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))
            >>> (+ Literal(-1))
            rdflib.term.Literal('-1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))
            >>> from rdflib.namespace import XSD
            >>> (+ Literal("-1", datatype=XSD.integer))
            rdflib.term.Literal('-1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            >>> (+ Literal("1"))
            Traceback (most recent call last):
              File "<stdin>", line 1, in <module>
            TypeError: Not a number; rdflib.term.Literal('1')
            """
            if isinstance(self.value, (int, long_type, float)):
                return Literal(self.value.__pos__())
            else:
                raise TypeError(f"Not a number; {self!r}")

        def __abs__(self) -> Literal:
            """
            >>> abs(Literal(-1))
            rdflib.term.Literal('1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            >>> from rdflib.namespace import XSD
            >>> abs( Literal("-1", datatype=XSD.integer))
            rdflib.term.Literal('1', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            >>> abs(Literal("1"))
            Traceback (most recent call last):
              File "<stdin>", line 1, in <module>
            TypeError: Not a number; rdflib.term.Literal('1')
            """
            if isinstance(self.value, (int, long_type, float)):
                return Literal(self.value.__abs__())
            else:
                raise TypeError(f"Not a number; {self!r}")

        def __invert__(self) -> Literal:
            """
            >>> ~(Literal(-1))
            rdflib.term.Literal('0', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            >>> from rdflib.namespace import XSD
            >>> ~( Literal("-1", datatype=XSD.integer))
            rdflib.term.Literal('0', datatype=rdflib.term.URIRef('http://www.w3.org/2001/XMLSchema#integer'))

            Not working:

            >>> ~(Literal("1"))
            Traceback (most recent call last):
              File "<stdin>", line 1, in <module>
            TypeError: Not a number; rdflib.term.Literal('1')
            """
            if isinstance(self.value, (int, long_type, float)):
                # type error: Unsupported operand type for ~ ("float")
                return Literal(self.value.__invert__())  # type: ignore[operator] # FIXME
            else:
                raise TypeError(f"Not a number; {self!r}")

        def __gt__(self, other: Any) -> bool:
            """

            This implements ordering for Literals,
            the other comparison methods delegate here

            This tries to implement this:
            http://www.w3.org/TR/sparql11-query/#modOrderBy

            In short, Literals with compatible data-types are ordered in value
            space, i.e.
            >>> from rdflib import XSD

            >>> Literal(1) > Literal(2) # int/int
            False
            >>> Literal(2.0) > Literal(1) # double/int
            True
            >>> from decimal import Decimal
            >>> Literal(Decimal("3.3")) > Literal(2.0) # decimal/double
            True
            >>> Literal(Decimal("3.3")) < Literal(4.0) # decimal/double
            True
            >>> Literal('b') > Literal('a') # plain lit/plain lit
            True
            >>> Literal('b') > Literal('a', datatype=XSD.string) # plain lit/xsd:str
            True

            Incompatible datatype mismatches ordered by DT

            >>> Literal(1) > Literal("2") # int>string
            False

            Langtagged literals by lang tag
            >>> Literal("a", lang="en") > Literal("a", lang="fr")
            False
            """
            if other is None:
                return True  # Everything is greater than None
            if isinstance(other, Literal):
                # Fast path for comparing numeric literals
                # that are not ill-typed and don't have a None value
                if (
                    (
                        self.datatype in _NUMERIC_LITERAL_TYPES
                        and other.datatype in _NUMERIC_LITERAL_TYPES
                    )
                    and ((not self.ill_typed) and (not other.ill_typed))
                    and (self.value is not None and other.value is not None)
                ):
                    return self.value > other.value

                # plain-literals and xsd:string literals
                # are "the same"
                dtself = rdflib.util._coalesce(self.datatype, default=_XSD_STRING)
                dtother = rdflib.util._coalesce(other.datatype, default=_XSD_STRING)

                if dtself != dtother:
                    if rdflib.DAWG_LITERAL_COLLATION:
                        return NotImplemented
                    else:
                        return dtself > dtother

                if self.language != other.language:
                    if not self.language:
                        return False
                    elif not other.language:
                        return True
                    else:
                        return self.language > other.language

                if self.value is not None and other.value is not None:
                    if type(self.value) in _TOTAL_ORDER_CASTERS:
                        caster = _TOTAL_ORDER_CASTERS[type(self.value)]
                        return caster(self.value) > caster(other.value)

                    try:
                        return self.value > other.value
                    except TypeError:
                        pass

                if str(self) != str(other):
                    return str(self) > str(other)

                # same language, same lexical form, check real dt
                # plain-literals come before xsd:string!
                if self.datatype != other.datatype:
                    if self.datatype is None:
                        return False
                    elif other.datatype is None:
                        return True
                    else:
                        return self.datatype > other.datatype

                return False  # they are the same

            elif isinstance(other, Node):
                return True  # Literal are the greatest!
            else:
                return NotImplemented  # we can only compare to nodes

        def __lt__(self, other: Any) -> bool:
            if other is None:
                return False  # Nothing is less than None
            if isinstance(other, Literal):
                try:
                    return not self.__gt__(other) and not self.eq(other)
                except TypeError:
                    return NotImplemented
            if isinstance(other, Node):
                return False  # all nodes are less-than Literals

            return NotImplemented

        def __le__(self, other: Any) -> bool:
            """
            >>> from rdflib.namespace import XSD
            >>> Literal('2007-01-01T10:00:00', datatype=XSD.dateTime
            ...     ) <= Literal('2007-01-01T10:00:00', datatype=XSD.dateTime)
            True
            """
            r = self.__lt__(other)
            if r:
                return True
            try:
                return self.eq(other)
            except TypeError:
                return NotImplemented

        def __ge__(self, other: Any) -> bool:
            r = self.__gt__(other)
            if r:
                return True
            try:
                return self.eq(other)
            except TypeError:
                return NotImplemented

        def _comparable_to(self, other: Any) -> bool:
            """
            Helper method to decide which things are meaningful to
            rich-compare with this literal
            """
            if isinstance(other, Literal):
                if self.datatype is not None and other.datatype is not None:
                    # two datatyped literals
                    if (
                        self.datatype not in XSDToPython
                        or other.datatype not in XSDToPython
                    ):
                        # non XSD DTs must match
                        if self.datatype != other.datatype:
                            return False

                else:
                    # xsd:string may be compared with plain literals
                    if not (self.datatype == _XSD_STRING and not other.datatype) or (
                        other.datatype == _XSD_STRING and not self.datatype
                    ):
                        return False

                    # if given lang-tag has to be case insensitive equal
                    if (self.language or "").lower() != (other.language or "").lower():
                        return False

            return True

        # type error: Signature of "__hash__" incompatible with supertype "Identifier"
        #  Superclass: def __hash__(self: str) -> int
        #  Subclass: def __hash__(self) -> int
        #  NOTE for type ignore: This can possibly be fixed by changing how __hash__ is implemented in Identifier

        def __hash__(self) -> int:  # type: ignore[override]
            """
            >>> from rdflib.namespace import XSD
            >>> a = {Literal('1', datatype=XSD.integer):'one'}
            >>> Literal('1', datatype=XSD.double) in a
            False

            "Called for the key object for dictionary operations,
            and by the built-in function hash(). Should return
            a 32-bit integer usable as a hash value for
            dictionary operations. The only required property
            is that objects which compare equal have the same
            hash value; it is advised to somehow mix together
            (e.g., using exclusive or) the hash values for the
            components of the object that also play a part in
            comparison of objects." -- 3.4.1 Basic customization (Python)

            "Two literals are equal if and only if all of the following hold:
            * The strings of the two lexical forms compare equal, character by
            character.
            * Either both or neither have language tags.
            * The language tags, if any, compare equal.
            * Either both or neither have datatype URIs.
            * The two datatype URIs, if any, compare equal, character by
            character."
            -- 6.5.1 Literal Equality (RDF: Concepts and Abstract Syntax)

            """
            # don't use super()... for efficiency reasons, see Identifier.__hash__
            res = str.__hash__(self)
            # Directly accessing the member is faster than the property.
            if self._language:
                res ^= hash(self._language.lower())
            if self._datatype is not None:
                res ^= hash(self._datatype)
            return res

        def __eq__(self, other: Any) -> bool:
            """
            Literals are only equal to other literals.

            "Two literals are equal if and only if all of the following hold:
            * The strings of the two lexical forms compare equal, character by character.
            * Either both or neither have language tags.
            * The language tags, if any, compare equal.
            * Either both or neither have datatype URIs.
            * The two datatype URIs, if any, compare equal, character by character."
            -- 6.5.1 Literal Equality (RDF: Concepts and Abstract Syntax)

            >>> Literal("1", datatype=URIRef("foo")) == Literal("1", datatype=URIRef("foo"))
            True
            >>> Literal("1", datatype=URIRef("foo")) == Literal("1", datatype=URIRef("foo2"))
            False

            >>> Literal("1", datatype=URIRef("foo")) == Literal("2", datatype=URIRef("foo"))
            False
            >>> Literal("1", datatype=URIRef("foo")) == "asdf"
            False
            >>> from rdflib import XSD
            >>> Literal('2007-01-01', datatype=XSD.date) == Literal('2007-01-01', datatype=XSD.date)
            True
            >>> Literal('2007-01-01', datatype=XSD.date) == date(2007, 1, 1)
            False
            >>> Literal("one", lang="en") == Literal("one", lang="en")
            True
            >>> Literal("hast", lang='en') == Literal("hast", lang='de')
            False
            >>> Literal("1", datatype=XSD.integer) == Literal(1)
            True
            >>> Literal("1", datatype=XSD.integer) == Literal("01", datatype=XSD.integer)
            True

            """
            if self is other:
                return True
            if other is None:
                return False
            # Directly accessing the member is faster than the property.
            if isinstance(other, Literal):
                return (
                    self._datatype == other._datatype
                    and (self._language.lower() if self._language else None)
                    == (other._language.lower() if other._language else None)
                    and str.__eq__(self, other)
                )

            return False

        def eq(self, other: Any) -> bool:
            """
            Compare the value of this literal with something else

            Either, with the value of another literal
            comparisons are then done in literal "value space",
            and according to the rules of XSD subtype-substitution/type-promotion

            OR, with a python object:

            basestring objects can be compared with plain-literals,
            or those with datatype xsd:string

            bool objects with xsd:boolean

            a int, long or float with numeric xsd types

            isodate date,time,datetime objects with xsd:date,xsd:time or xsd:datetime

            Any other operations returns NotImplemented

            """
            if isinstance(other, Literal):
                # Fast path for comparing numeric literals
                # that are not ill-typed and don't have a None value
                if (
                    (
                        self.datatype in _NUMERIC_LITERAL_TYPES
                        and other.datatype in _NUMERIC_LITERAL_TYPES
                    )
                    and ((not self.ill_typed) and (not other.ill_typed))
                    and (self.value is not None and other.value is not None)
                ):
                    if self.value is not None and other.value is not None:
                        return self.value == other.value
                    else:
                        if str.__eq__(self, other):
                            return True
                        raise TypeError(
                            # TODO: Should this use repr strings in the error message?
                            "I cannot know that these two lexical forms do not map to the "
                            f"same value: {self} and {other}"
                        )
                if (self.language or "").lower() != (other.language or "").lower():
                    return False

                dtself = rdflib.util._coalesce(self.datatype, default=_XSD_STRING)
                dtother = rdflib.util._coalesce(other.datatype, default=_XSD_STRING)

                if dtself == _XSD_STRING and dtother == _XSD_STRING:
                    # string/plain literals, compare on lexical form
                    return str.__eq__(self, other)

                # XML can be compared to HTML, only if html5rdf is enabled
                if (
                    (dtself in _XML_COMPARABLE and dtother in _XML_COMPARABLE)
                    and
                    # Ill-typed can be None if unknown, but we don't want it to be True.
                    ((self.ill_typed is not True) and (other.ill_typed is not True))
                    and (self.value is not None and other.value is not None)
                ):
                    return _isEqualXMLNode(self.value, other.value)

                if dtself != dtother:
                    if rdflib.DAWG_LITERAL_COLLATION:
                        raise TypeError(
                            f"I don't know how to compare literals with datatypes {self.datatype} and {other.datatype}"
                        )
                    else:
                        return False

                # matching non-string DTs now - do we compare values or
                # lexical form first?  comparing two ints is far quicker -
                # maybe there are counter examples

                if self.value is not None and other.value is not None:
                    return self.value == other.value
                else:
                    if str.__eq__(self, other):
                        return True

                    if self.datatype == _XSD_STRING:
                        return False  # string value space=lexical space

                    # matching DTs, but not matching, we cannot compare!
                    raise TypeError(
                        # TODO: Should this use repr strings in the error message?
                        "I cannot know that these two lexical forms do not map to the same "
                        f"value: {self} and {other}"
                    )

            elif isinstance(other, Node):
                return False  # no non-Literal nodes are equal to a literal

            elif isinstance(other, str):
                # only plain-literals can be directly compared to strings

                # TODO: Is "blah"@en eq "blah" ?
                if self.language is not None:
                    return False

                if self.datatype == _XSD_STRING or self.datatype is None:
                    return str(self) == other

            elif isinstance(other, (int, long_type, float)):
                if self.datatype in _NUMERIC_LITERAL_TYPES:
                    return self.value == other
            elif isinstance(other, (date, datetime, time)):
                if self.datatype in (_XSD_DATETIME, _XSD_DATE, _XSD_TIME):
                    return self.value == other
            elif isinstance(other, (timedelta, Duration)):
                if self.datatype in (
                    _XSD_DURATION,
                    _XSD_DAYTIMEDURATION,
                    _XSD_YEARMONTHDURATION,
                ):
                    return self.value == other
            # NOTE for type ignore: bool is a subclass of int so this won't ever run.
            elif isinstance(other, bool):  # type: ignore[unreachable, unused-ignore]
                if self.datatype == _XSD_BOOLEAN:
                    return self.value == other

            return NotImplemented

        def neq(self, other: Any) -> bool:
            return not self.eq(other)

        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str:
            r'''
            Returns a representation in the N3 format.

            Examples::

                >>> Literal("foo").n3()
                '"foo"'

            Strings with newlines or triple-quotes::

                >>> Literal("foo\nbar").n3()
                '"""foo\nbar"""'

                >>> Literal("''\'").n3()
                '"\'\'\'"'

                >>> Literal('"""').n3()
                '"\\"\\"\\""'

            Language::

                >>> Literal("hello", lang="en").n3()
                '"hello"@en'

            Datatypes::

                >>> Literal(1).n3()
                '"1"^^<http://www.w3.org/2001/XMLSchema#integer>'

                >>> Literal(1.0).n3()
                '"1.0"^^<http://www.w3.org/2001/XMLSchema#double>'

                >>> Literal(True).n3()
                '"true"^^<http://www.w3.org/2001/XMLSchema#boolean>'

            Datatype and language isn't allowed (datatype takes precedence)::

                >>> Literal(1, lang="en").n3()
                '"1"^^<http://www.w3.org/2001/XMLSchema#integer>'

            Custom datatype::

                >>> footype = URIRef("http://example.org/ns#foo")
                >>> Literal("1", datatype=footype).n3()
                '"1"^^<http://example.org/ns#foo>'

            Passing a namespace-manager will use it to abbreviate datatype URIs:

                >>> from rdflib import Graph
                >>> Literal(1).n3(Graph().namespace_manager)
                '"1"^^xsd:integer'
            '''
            if namespace_manager:
                return self._literal_n3(qname_callback=namespace_manager.normalizeUri)
            else:
                return self._literal_n3()

        def _literal_n3(
            self,
            use_plain: bool = False,
            qname_callback: Optional[Callable[[URIRef], Optional[str]]] = None,
        ) -> str:
            """
            Using plain literal (shorthand) output::
                >>> from rdflib.namespace import XSD

                >>> Literal(1)._literal_n3(use_plain=True)
                '1'

                >>> Literal(1.0)._literal_n3(use_plain=True)
                '1e+00'

                >>> Literal(1.0, datatype=XSD.decimal)._literal_n3(use_plain=True)
                '1.0'

                >>> Literal(1.0, datatype=XSD.float)._literal_n3(use_plain=True)
                '"1.0"^^<http://www.w3.org/2001/XMLSchema#float>'

                >>> Literal("foo", datatype=XSD.string)._literal_n3(
                ...         use_plain=True)
                '"foo"^^<http://www.w3.org/2001/XMLSchema#string>'

                >>> Literal(True)._literal_n3(use_plain=True)
                'true'

                >>> Literal(False)._literal_n3(use_plain=True)
                'false'

                >>> Literal(1.91)._literal_n3(use_plain=True)
                '1.91e+00'

                Only limited precision available for floats:
                >>> Literal(0.123456789)._literal_n3(use_plain=True)
                '1.234568e-01'

                >>> Literal('0.123456789',
                ...     datatype=XSD.decimal)._literal_n3(use_plain=True)
                '0.123456789'

            Using callback for datatype QNames::

                >>> Literal(1)._literal_n3(
                ...         qname_callback=lambda uri: "xsd:integer")
                '"1"^^xsd:integer'

            """
            if use_plain and self.datatype in _PLAIN_LITERAL_TYPES:
                if self.value is not None:
                    # If self is inf or NaN, we need a datatype
                    # (there is no plain representation)
                    if self.datatype in _NUMERIC_INF_NAN_LITERAL_TYPES:
                        try:
                            v = float(self)
                            if math.isinf(v) or math.isnan(v):
                                return self._literal_n3(False, qname_callback)
                        except ValueError:
                            return self._literal_n3(False, qname_callback)

                    # this is a bit of a mess -
                    # we try to produce "pretty" output
                    # that is compatible with n3 (turtle) notation
                    if self.datatype == _XSD_DOUBLE:
                        return sub("\\.?0*e", "e", f"{float(self):e}")
                    elif self.datatype == _XSD_DECIMAL:
                        s = f"{self}"  # f"{self}" is faster than "%s" % self and str(self)
                        if "." not in s and "e" not in s and "E" not in s:
                            s += ".0"
                        return s
                    elif self.datatype == _XSD_BOOLEAN:
                        return f"{self}".lower()
                    else:
                        return f"{self}"

            encoded: str = self._quote_encode()

            datatype = self.datatype
            quoted_dt = None
            if datatype is not None:
                if qname_callback:
                    quoted_dt = qname_callback(datatype)
                if not quoted_dt:
                    quoted_dt = f"<{datatype}>"
                if datatype in _NUMERIC_INF_NAN_LITERAL_TYPES:
                    try:
                        v = float(self)
                        if math.isinf(v):
                            # py string reps: float: 'inf', Decimal: 'Infinity"
                            # both need to become "INF" in xsd datatypes
                            encoded = encoded.replace("inf", "INF").replace(
                                "Infinity", "INF"
                            )
                        if math.isnan(v):
                            encoded = encoded.replace("nan", "NaN")
                    except ValueError:
                        # if we can't cast to float something is wrong, but we can
                        # still serialize. Warn user about it
                        warnings.warn(f"Serializing weird numerical {self!r}")

            language = self.language
            if language:
                return f"{encoded}@{language}"
            elif datatype:
                return f"{encoded}^^{quoted_dt}"
            else:
                return encoded

        def _quote_encode(self) -> str:
            # This simpler encoding doesn't work; a newline gets encoded as "\\n",
            # which is ok in sourcecode, but we want "\n".
            # encoded = self.encode('unicode-escape').replace(
            #        '\\', '\\\\').replace('"','\\"')
            # encoded = self.replace.replace('\\', '\\\\').replace('"','\\"')

            # NOTE: Could in theory chose quotes based on quotes appearing in the
            # string, i.e. '"' and "'", but N3/turtle doesn't allow "'"(?).

            if "\n" in self:
                # Triple quote this string.
                encoded = self.replace("\\", "\\\\")
                if '"""' in self:
                    # is this ok?
                    encoded = encoded.replace('"""', '\\"\\"\\"')
                if encoded[-1] == '"' and encoded[-2] != "\\":
                    encoded = encoded[:-1] + "\\" + '"'
                # TODO: Replace usage of %s here with fstrings
                # when we have ability to escape \r and \n inside
                # f-string inline function calls
                return '"""%s"""' % encoded.replace("\r", "\\r")
            else:
                return '"%s"' % self.replace("\n", "\\n").replace("\\", "\\\\").replace(
                    '"', '\\"'
                ).replace("\r", "\\r")

        def __repr__(self) -> str:
            args = [str.__repr__(self)]
            if self.language is not None:
                args.append("lang=" + repr(self.language))
            if self.datatype is not None:
                args.append("datatype=" + repr(self.datatype))
            if self.__class__ == Literal:
                clsName = "rdflib.term.Literal"  # noqa: N806
            else:
                clsName = self.__class__.__name__  # noqa: N806
            return f"{clsName}({', '.join(args)})"

        def toPython(self) -> Any:  # noqa: N802
            """
            Returns an appropriate python datatype derived from this RDF Literal
            """

            if self.value is not None:
                return self.value
            return self

    def _parseXML(xmlstring: str) -> xml.dom.minidom.Document:  # noqa: N802
        retval = xml.dom.minidom.parseString(
            f"<rdflibtoplevelelement>{xmlstring}</rdflibtoplevelelement>"
        )
        retval.normalize()
        return retval

    def _parse_html(lexical_form: str) -> xml.dom.minidom.DocumentFragment:
        """
        Parse the lexical form of an HTML literal into a document fragment
        using the ``dom`` from html5rdf tree builder.

        :param lexical_form: The lexical form of the HTML literal.
        :return: A document fragment representing the HTML literal.
        :raises: `html5rdf.html5parser.ParseError` if the lexical form is
            not valid HTML.
        """
        parser = html5rdf.HTMLParser(
            tree=html5rdf.treebuilders.getTreeBuilder("dom"), strict=True
        )
        try:
            result: xml.dom.minidom.DocumentFragment = parser.parseFragment(lexical_form)
        except html5rdf.html5parser.ParseError as e:
            logger.info(f"Failed to parse HTML: {e}")
            raise e
        result.normalize()
        return result

    def _write_html(value: xml.dom.minidom.DocumentFragment) -> bytes:
        """
        Serialize a document fragment representing an HTML literal into
        its lexical form.

        :param value: A document fragment representing an HTML literal.
        :return: The lexical form of the HTML literal.
        """
        result = html5rdf.serialize(value, tree="dom")
        return result

    def _writeXML(  # noqa: N802
        xmlnode: Union[xml.dom.minidom.Document, xml.dom.minidom.DocumentFragment]
    ) -> bytes:
        if isinstance(xmlnode, xml.dom.minidom.DocumentFragment):
            d = xml.dom.minidom.Document()
            d.childNodes += xmlnode.childNodes
            xmlnode = d
        s = xmlnode.toxml("utf-8")
        # for clean round-tripping, remove headers -- I have great and
        # specific worries that this will blow up later, but this margin
        # is too narrow to contain them
        if s.startswith(b'<?xml version="1.0" encoding="utf-8"?>'):
            s = s[38:]
        if s.startswith(b"<rdflibtoplevelelement>"):
            s = s[23:-24]
        if s == b"<rdflibtoplevelelement/>":
            s = b""
        return s

    def _unhexlify(value: Union[str, bytes, Literal]) -> bytes:
        # In Python 3.2, unhexlify does not support str (only bytes)
        if isinstance(value, str):
            value = value.encode()
        return unhexlify(value)

    def _parseBoolean(value: Union[str, bytes]) -> bool:  # noqa: N802
        """
        Boolean is a datatype with value space {true,false},
        lexical space {"true", "false","1","0"} and
        lexical-to-value mapping {"true"→true, "false"→false, "1"→true, "0"→false}.
        """
        true_accepted_values = ["1", "true", b"1", b"true"]
        false_accepted_values = ["0", "false", b"0", b"false"]
        new_value = value.lower()
        if new_value in true_accepted_values:
            return True
        if new_value not in false_accepted_values:
            warnings.warn(
                f"Parsing weird boolean, {value!r} does not map to True or False",
                category=UserWarning,
            )
        return False

    def _well_formed_by_value(lexical: Union[str, bytes], value: Any) -> bool:
        """
        This function is used as the fallback for detecting ill-typed/ill-formed
        literals and operates on the asumption that if a value (i.e.
        `Literal.value`) could be determined for a Literal then it is not
        ill-typed/ill-formed.

        This function will be called with `Literal.lexical` and `Literal.value` as arguments.
        """
        return value is not None

    def _well_formed_unsignedlong(lexical: Union[str, bytes], value: Any) -> bool:
        """
        xsd:unsignedInteger and xsd:unsignedLong must not be negative
        """
        return len(lexical) > 0 and isinstance(value, long_type) and value >= 0

    def _well_formed_boolean(lexical: Union[str, bytes], value: Any) -> bool:
        """
        Boolean is a datatype with value space {true,false},
        lexical space {"true", "false","1","0"} and
        lexical-to-value mapping {"true"→true, "false"→false, "1"→true, "0"→false}.
        """
        return lexical in ("true", b"true", "false", b"false", "1", b"1", "0", b"0")

    def _well_formed_int(lexical: Union[str, bytes], value: Any) -> bool:
        """
        The value space of xs:int is the set of common single size integers (32 bits),
        i.e., the integers between -2147483648 and 2147483647,
        its lexical space allows any number of insignificant leading zeros.
        """
        return (
            len(lexical) > 0
            and isinstance(value, int)
            and (-2147483648 <= value <= 2147483647)
        )

    def _well_formed_unsignedint(lexical: Union[str, bytes], value: Any) -> bool:
        """
        xsd:unsignedInt has a 32bit value of between 0 and 4294967295
        """
        return len(lexical) > 0 and isinstance(value, int) and (0 <= value <= 4294967295)

    def _well_formed_short(lexical: Union[str, bytes], value: Any) -> bool:
        """
        The value space of xs:short is the set of common short integers (16 bits),
        i.e., the integers between -32768 and 32767,
        its lexical space allows any number of insignificant leading zeros.
        """
        return len(lexical) > 0 and isinstance(value, int) and (-32768 <= value <= 32767)

    def _well_formed_unsignedshort(lexical: Union[str, bytes], value: Any) -> bool:
        """
        xsd:unsignedShort has a 16bit value of between 0 and 65535
        """
        return len(lexical) > 0 and isinstance(value, int) and (0 <= value <= 65535)

    def _well_formed_byte(lexical: Union[str, bytes], value: Any) -> bool:
        """
        The value space of xs:byte is the set of common single byte integers (8 bits),
        i.e., the integers between -128 and 127,
        its lexical space allows any number of insignificant leading zeros.
        """
        return len(lexical) > 0 and isinstance(value, int) and (-128 <= value <= 127)

    def _well_formed_unsignedbyte(lexical: Union[str, bytes], value: Any) -> bool:
        """
        xsd:unsignedByte has a 8bit value of between 0 and 255
        """
        return len(lexical) > 0 and isinstance(value, int) and (0 <= value <= 255)

    def _well_formed_non_negative_integer(lexical: Union[str, bytes], value: Any) -> bool:
        return isinstance(value, int) and value >= 0

    def _well_formed_positive_integer(lexical: Union[str, bytes], value: Any) -> bool:
        return isinstance(value, int) and value > 0

    def _well_formed_non_positive_integer(lexical: Union[str, bytes], value: Any) -> bool:
        return isinstance(value, int) and value <= 0

    def _well_formed_negative_integer(lexical: Union[str, bytes], value: Any) -> bool:
        return isinstance(value, int) and value < 0

    # Cannot import Namespace/XSD because of circular dependencies
    _XSD_PFX = "http://www.w3.org/2001/XMLSchema#"
    _RDF_PFX = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"

    _RDF_XMLLITERAL = URIRef(_RDF_PFX + "XMLLiteral")
    _RDF_HTMLLITERAL = URIRef(_RDF_PFX + "HTML")

    _XSD_STRING = URIRef(_XSD_PFX + "string")
    _XSD_NORMALISED_STRING = URIRef(_XSD_PFX + "normalizedString")
    _XSD_TOKEN = URIRef(_XSD_PFX + "token")

    _XSD_FLOAT = URIRef(_XSD_PFX + "float")
    _XSD_DOUBLE = URIRef(_XSD_PFX + "double")
    _XSD_DECIMAL = URIRef(_XSD_PFX + "decimal")
    _XSD_INTEGER = URIRef(_XSD_PFX + "integer")
    _XSD_BOOLEAN = URIRef(_XSD_PFX + "boolean")

    _XSD_DATETIME = URIRef(_XSD_PFX + "dateTime")
    _XSD_DATE = URIRef(_XSD_PFX + "date")
    _XSD_TIME = URIRef(_XSD_PFX + "time")
    _XSD_DURATION = URIRef(_XSD_PFX + "duration")
    _XSD_DAYTIMEDURATION = URIRef(_XSD_PFX + "dayTimeDuration")
    _XSD_YEARMONTHDURATION = URIRef(_XSD_PFX + "yearMonthDuration")

    _OWL_RATIONAL = URIRef("http://www.w3.org/2002/07/owl#rational")
    _XSD_B64BINARY = URIRef(_XSD_PFX + "base64Binary")
    _XSD_HEXBINARY = URIRef(_XSD_PFX + "hexBinary")
    _XSD_GYEAR = URIRef(_XSD_PFX + "gYear")
    _XSD_GYEARMONTH = URIRef(_XSD_PFX + "gYearMonth")
    # TODO: gMonthDay, gDay, gMonth

    _NUMERIC_LITERAL_TYPES: Tuple[URIRef, ...] = (
        _XSD_INTEGER,
        _XSD_DECIMAL,
        _XSD_DOUBLE,
        URIRef(_XSD_PFX + "float"),
        URIRef(_XSD_PFX + "byte"),
        URIRef(_XSD_PFX + "int"),
        URIRef(_XSD_PFX + "long"),
        URIRef(_XSD_PFX + "negativeInteger"),
        URIRef(_XSD_PFX + "nonNegativeInteger"),
        URIRef(_XSD_PFX + "nonPositiveInteger"),
        URIRef(_XSD_PFX + "positiveInteger"),
        URIRef(_XSD_PFX + "short"),
        URIRef(_XSD_PFX + "unsignedByte"),
        URIRef(_XSD_PFX + "unsignedInt"),
        URIRef(_XSD_PFX + "unsignedLong"),
        URIRef(_XSD_PFX + "unsignedShort"),
    )

    # these have "native" syntax in N3/SPARQL
    _PLAIN_LITERAL_TYPES: Tuple[URIRef, ...] = (
        _XSD_INTEGER,
        _XSD_BOOLEAN,
        _XSD_DOUBLE,
        _XSD_DECIMAL,
        _OWL_RATIONAL,
    )

    # these have special INF and NaN XSD representations
    _NUMERIC_INF_NAN_LITERAL_TYPES: Tuple[URIRef, ...] = (
        URIRef(_XSD_PFX + "float"),
        _XSD_DOUBLE,
        _XSD_DECIMAL,
    )

    # these need dedicated operators
    _DATE_AND_TIME_TYPES: Tuple[URIRef, ...] = (
        _XSD_DATETIME,
        _XSD_DATE,
        _XSD_TIME,
    )

    # These are recognized datatype IRIs
    # (https://www.w3.org/TR/rdf11-concepts/#dfn-recognized-datatype-iris) that
    # represents durations.
    _TIME_DELTA_TYPES: Tuple[URIRef, ...] = (
        _XSD_DURATION,
        _XSD_DAYTIMEDURATION,
    )

    _ALL_DATE_AND_TIME_TYPES: Tuple[URIRef, ...] = _DATE_AND_TIME_TYPES + _TIME_DELTA_TYPES

    # the following types need special treatment for reasonable sorting because
    # certain instances can't be compared to each other. We treat this by
    # partitioning and then sorting within those partitions.
    _TOTAL_ORDER_CASTERS: Dict[Type[Any], Callable[[Any], Any]] = {
        datetime: lambda value: (
            # naive vs. aware
            value.tzinfo is not None and value.tzinfo.utcoffset(value) is not None,
            value,
        ),
        time: lambda value: (
            # naive vs. aware
            value.tzinfo is not None and value.tzinfo.utcoffset(None) is not None,
            value,
        ),
        xml.dom.minidom.Document: lambda value: value.toxml(),
    }

    _STRING_LITERAL_TYPES: Tuple[URIRef, ...] = (
        _XSD_STRING,
        _RDF_XMLLITERAL,
        _RDF_HTMLLITERAL,
        URIRef(_XSD_PFX + "normalizedString"),
        URIRef(_XSD_PFX + "token"),
    )

    _StrT = TypeVar("_StrT", bound=str)

    def _py2literal(
        obj: Any,
        pType: Any,  # noqa: N803
        castFunc: Optional[Callable[[Any], Any]],  # noqa: N803
        dType: Optional[_StrT],  # noqa: N803
    ) -> Tuple[Any, Optional[_StrT]]:
        if castFunc is not None:
            return castFunc(obj), dType
        elif dType is not None:
            return obj, dType
        else:
            return obj, None

    def _castPythonToLiteral(  # noqa: N802
        obj: Any, datatype: Optional[str]
    ) -> Tuple[Any, Optional[str]]:
        """
        Casts a tuple of a python type and a special datatype URI to a tuple of the lexical value and a
        datatype URI (or None)
        """
        castFunc: Optional[Callable[[Any], Union[str, bytes]]]  # noqa: N806
        dType: Optional[str]  # noqa: N806
        for (pType, dType), castFunc in _SpecificPythonToXSDRules:  # noqa: N806
            if isinstance(obj, pType) and dType == datatype:
                return _py2literal(obj, pType, castFunc, dType)

        for pType, (castFunc, dType) in _GenericPythonToXSDRules:  # noqa: N806
            if isinstance(obj, pType):
                return _py2literal(obj, pType, castFunc, dType)
        return obj, None  # TODO: is this right for the fall through case?

    # Mappings from Python types to XSD datatypes and back (borrowed from sparta)
    # datetime instances are also instances of date... so we need to order these.

    # SPARQL/Turtle/N3 has shortcuts for integer, double, decimal
    # python has only float - to be in tune with sparql/n3/turtle
    # we default to XSD.double for float literals

    # python ints are promoted to longs when overflowing
    # python longs have no limit
    # both map to the abstract integer type,
    # rather than some concrete bit-limited datatype
    _GenericPythonToXSDRules: List[
        Tuple[Type[Any], Tuple[Optional[Callable[[Any], Union[str, bytes]]], Optional[str]]]
    ] = [
        (str, (None, None)),
        (float, (None, _XSD_DOUBLE)),
        (bool, (lambda i: str(i).lower(), _XSD_BOOLEAN)),
        (int, (None, _XSD_INTEGER)),
        (long_type, (None, _XSD_INTEGER)),
        (Decimal, (lambda i: f"{i:f}", _XSD_DECIMAL)),
        (datetime, (lambda i: i.isoformat(), _XSD_DATETIME)),
        (date, (lambda i: i.isoformat(), _XSD_DATE)),
        (time, (lambda i: i.isoformat(), _XSD_TIME)),
        (Duration, (lambda i: duration_isoformat(i), _XSD_DURATION)),
        (timedelta, (lambda i: duration_isoformat(i), _XSD_DAYTIMEDURATION)),
        (xml.dom.minidom.Document, (_writeXML, _RDF_XMLLITERAL)),
        (Fraction, (None, _OWL_RATIONAL)),
    ]

    if html5rdf is not None:
        # This is a bit dirty, by accident the html5rdf parser produces
        # DocumentFragments, and the xml parser Documents, letting this
        # decide what datatype to use makes roundtripping easier, but its a
        # bit random.

        # This must happen before _GenericPythonToXSDRules is assigned to
        # _OriginalGenericPythonToXSDRules.
        _GenericPythonToXSDRules.append(
            (xml.dom.minidom.DocumentFragment, (_write_html, _RDF_HTMLLITERAL))
        )

    _OriginalGenericPythonToXSDRules = list(_GenericPythonToXSDRules)

    _SpecificPythonToXSDRules: List[
        Tuple[Tuple[Type[Any], str], Optional[Callable[[Any], Union[str, bytes]]]]
    ] = [
        ((date, _XSD_GYEAR), lambda val: val.strftime("%Y").zfill(4)),
        ((date, _XSD_GYEARMONTH), lambda val: val.strftime("%Y-%m").zfill(7)),
        ((str, _XSD_HEXBINARY), hexlify),
        ((bytes, _XSD_HEXBINARY), hexlify),
        ((str, _XSD_B64BINARY), b64encode),
        ((bytes, _XSD_B64BINARY), b64encode),
    ]

    _OriginalSpecificPythonToXSDRules = list(_SpecificPythonToXSDRules)

    XSDToPython: Dict[Optional[str], Optional[Callable[[str], Any]]] = {
        None: None,  # plain literals map directly to value space
        URIRef(_XSD_PFX + "time"): parse_time,
        URIRef(_XSD_PFX + "date"): parse_xsd_date,
        URIRef(_XSD_PFX + "gYear"): parse_xsd_gyear,
        URIRef(_XSD_PFX + "gYearMonth"): parse_xsd_gyearmonth,
        URIRef(_XSD_PFX + "dateTime"): parse_datetime,
        URIRef(_XSD_PFX + "duration"): parse_xsd_duration,
        URIRef(_XSD_PFX + "dayTimeDuration"): parse_xsd_duration,
        URIRef(_XSD_PFX + "yearMonthDuration"): parse_xsd_duration,
        URIRef(_XSD_PFX + "hexBinary"): _unhexlify,
        URIRef(_XSD_PFX + "string"): None,
        URIRef(_XSD_PFX + "normalizedString"): None,
        URIRef(_XSD_PFX + "token"): None,
        URIRef(_XSD_PFX + "language"): None,
        URIRef(_XSD_PFX + "boolean"): _parseBoolean,
        URIRef(_XSD_PFX + "decimal"): Decimal,
        URIRef(_XSD_PFX + "integer"): long_type,
        URIRef(_XSD_PFX + "nonPositiveInteger"): long_type,
        URIRef(_XSD_PFX + "long"): long_type,
        URIRef(_XSD_PFX + "nonNegativeInteger"): long_type,
        URIRef(_XSD_PFX + "negativeInteger"): long_type,
        URIRef(_XSD_PFX + "int"): int,
        URIRef(_XSD_PFX + "unsignedLong"): long_type,
        URIRef(_XSD_PFX + "positiveInteger"): long_type,
        URIRef(_XSD_PFX + "short"): int,
        URIRef(_XSD_PFX + "unsignedInt"): int,
        URIRef(_XSD_PFX + "byte"): int,
        URIRef(_XSD_PFX + "unsignedShort"): int,
        URIRef(_XSD_PFX + "unsignedByte"): int,
        URIRef(_XSD_PFX + "float"): float,
        URIRef(_XSD_PFX + "double"): float,
        URIRef(_XSD_PFX + "base64Binary"): b64decode,
        URIRef(_XSD_PFX + "anyURI"): None,
        _RDF_XMLLITERAL: _parseXML,
    }

    if html5rdf is not None:
        # It is probably best to keep this close to the definition of
        # _GenericPythonToXSDRules so nobody misses it.
        XSDToPython[_RDF_HTMLLITERAL] = _parse_html
        _XML_COMPARABLE: Tuple[URIRef, ...] = (_RDF_XMLLITERAL, _RDF_HTMLLITERAL)
    else:
        _XML_COMPARABLE = (_RDF_XMLLITERAL,)

    _check_well_formed_types: Dict[URIRef, Callable[[Union[str, bytes], Any], bool]] = {
        URIRef(_XSD_PFX + "boolean"): _well_formed_boolean,
        URIRef(_XSD_PFX + "nonPositiveInteger"): _well_formed_non_positive_integer,
        URIRef(_XSD_PFX + "nonNegativeInteger"): _well_formed_non_negative_integer,
        URIRef(_XSD_PFX + "negativeInteger"): _well_formed_negative_integer,
        URIRef(_XSD_PFX + "positiveInteger"): _well_formed_positive_integer,
        URIRef(_XSD_PFX + "int"): _well_formed_int,
        URIRef(_XSD_PFX + "short"): _well_formed_short,
        URIRef(_XSD_PFX + "byte"): _well_formed_byte,
        URIRef(_XSD_PFX + "unsignedInt"): _well_formed_unsignedint,
        URIRef(_XSD_PFX + "unsignedLong"): _well_formed_unsignedlong,
        URIRef(_XSD_PFX + "unsignedShort"): _well_formed_unsignedshort,
        URIRef(_XSD_PFX + "unsignedByte"): _well_formed_unsignedbyte,
    }

    _toPythonMapping: Dict[Optional[str], Optional[Callable[[str], Any]]] = {}  # noqa: N816

    _toPythonMapping.update(XSDToPython)

    def _reset_bindings() -> None:
        """
        Reset lexical<->value space binding for `Literal`
        """
        _toPythonMapping.clear()
        _toPythonMapping.update(XSDToPython)

        _GenericPythonToXSDRules.clear()
        _GenericPythonToXSDRules.extend(_OriginalGenericPythonToXSDRules)

        _SpecificPythonToXSDRules.clear()
        _SpecificPythonToXSDRules.extend(_OriginalSpecificPythonToXSDRules)

    def _castLexicalToPython(  # noqa: N802
        lexical: Union[str, bytes], datatype: Optional[URIRef]
    ) -> Any:
        """
        Map a lexical form to the value-space for the given datatype
        :returns: a python object for the value or ``None``
        """
        try:
            conv_func = _toPythonMapping[datatype]
        except KeyError:
            # no conv_func -> unknown data-type
            return None

        if conv_func is not None:
            try:
                # type error: Argument 1 has incompatible type "Union[str, bytes]"; expected "str"
                # NOTE for type ignore: various functions in _toPythonMapping will
                # only work for str, so there is some inconsistency here, the right
                # approach may be to change lexical to be of str type but this will
                # require runtime changes.
                return conv_func(lexical)  # type: ignore[arg-type]
            except Exception:
                logger.warning(
                    f"Failed to convert Literal lexical form to value. Datatype={datatype}, Converter={conv_func}",
                    exc_info=True,
                )
                # not a valid lexical representation for this dt
                return None
        else:
            # no conv func means 1-1 lexical<->value-space mapping
            try:
                return str(lexical)
            except UnicodeDecodeError:
                # type error: Argument 1 to "str" has incompatible type "Union[str, bytes]"; expected "bytes"
                # NOTE for type ignore: code assumes that lexical is of type bytes
                # at this point.
                return str(lexical, "utf-8")  # type: ignore[arg-type]

    _AnyT = TypeVar("_AnyT", bound=Any)

    def _normalise_XSD_STRING(lexical_or_value: _AnyT) -> _AnyT:  # noqa: N802
        """
        Replaces \t, \n, \r (#x9 (tab), #xA (linefeed), and #xD (carriage return)) with space without any whitespace collapsing
        """
        if isinstance(lexical_or_value, str):
            # type error: Incompatible return value type (got "str", expected "_AnyT")  [return-value]
            # NOTE for type ignore: this is an issue with mypy: https://github.com/python/mypy/issues/10003
            return lexical_or_value.replace("\t", " ").replace("\n", " ").replace("\r", " ")  # type: ignore[return-value]
        return lexical_or_value

    def _strip_and_collapse_whitespace(lexical_or_value: _AnyT) -> _AnyT:
        if isinstance(lexical_or_value, str):
            # Use regex to substitute contiguous whitespace into a single whitespace. Strip trailing whitespace.
            # type error: Incompatible return value type (got "str", expected "_AnyT")  [return-value]
            # NOTE for type ignore: this is an issue with mypy: https://github.com/python/mypy/issues/10003
            return re.sub(" +", " ", lexical_or_value.strip())  # type: ignore[return-value]
        return lexical_or_value

    def bind(
        datatype: str,
        pythontype: Type[Any],
        constructor: Optional[Callable[[str], Any]] = None,
        lexicalizer: Optional[Callable[[Any], Union[str, bytes]]] = None,
        datatype_specific: bool = False,
    ) -> None:
        """
        register a new datatype<->pythontype binding

        :param constructor: an optional function for converting lexical forms
                            into a Python instances, if not given the pythontype
                            is used directly

        :param lexicalizer: an optional function for converting python objects to
                            lexical form, if not given object.__str__ is used

        :param datatype_specific: makes the lexicalizer function be accessible
                                  from the pair (pythontype, datatype) if set to True
                                  or from the pythontype otherwise.  False by default
        """
        if datatype_specific and datatype is None:
            raise Exception("No datatype given for a datatype-specific binding")

        if datatype in _toPythonMapping:
            logger.warning(f"datatype '{datatype}' was already bound. Rebinding.")

        if constructor is None:
            constructor = pythontype
        _toPythonMapping[datatype] = constructor
        if datatype_specific:
            _SpecificPythonToXSDRules.append(((pythontype, datatype), lexicalizer))
        else:
            _GenericPythonToXSDRules.append((pythontype, (lexicalizer, datatype)))

    class Variable(Identifier):
        """
        A Variable - this is used for querying, or in Formula aware
        graphs, where Variables can be stored
        """

        __slots__ = ()

        def __new__(cls, value: str) -> Variable:
            if len(value) == 0:
                raise Exception("Attempted to create variable with empty string as name!")
            if value[0] == "?":
                value = value[1:]
            return str.__new__(cls, value)

        def __repr__(self) -> str:
            if self.__class__ is Variable:
                clsName = "rdflib.term.Variable"  # noqa: N806
            else:
                clsName = self.__class__.__name__  # noqa: N806

            return f"{clsName}({str.__repr__(self)})"

        def toPython(self) -> str:  # noqa: N802
            return "?" + self

        def n3(self, namespace_manager: Optional[NamespaceManager] = None) -> str:
            return "?" + self

        def __reduce__(self) -> Tuple[Type[Variable], Tuple[str]]:
            return (Variable, (str(self),))

    # Nodes are ordered like this
    # See http://www.w3.org/TR/sparql11-query/#modOrderBy
    # we leave "space" for more subclasses of Node elsewhere
    # default-dict to grazefully fail for new subclasses
    _ORDERING: Dict[Type[Node], int] = defaultdict(int)
    _ORDERING.update({BNode: 10, Variable: 20, URIRef: 30, Literal: 40})

    def _isEqualXMLNode(  # noqa: N802
        node: Union[
            None,
            xml.dom.minidom.Attr,
            xml.dom.minidom.Comment,
            xml.dom.minidom.Document,
            xml.dom.minidom.DocumentFragment,
            xml.dom.minidom.DocumentType,
            xml.dom.minidom.Element,
            xml.dom.minidom.Entity,
            xml.dom.minidom.Notation,
            xml.dom.minidom.ProcessingInstruction,
            xml.dom.minidom.Text,
        ],
        other: Union[
            None,
            xml.dom.minidom.Attr,
            xml.dom.minidom.Comment,
            xml.dom.minidom.Document,
            xml.dom.minidom.DocumentFragment,
            xml.dom.minidom.DocumentType,
            xml.dom.minidom.Element,
            xml.dom.minidom.Entity,
            xml.dom.minidom.Notation,
            xml.dom.minidom.ProcessingInstruction,
            xml.dom.minidom.Text,
        ],
    ) -> bool:
        # importing xml.dom.minidom.Node as XMLNode to avoid confusion with
        # rdflib.term.Node
        from xml.dom.minidom import Node as XMLNode

        def recurse():
            # Recursion through the children
            # In Python2, the semantics of 'map' is such that the check on
            # length would be unnecessary. In Python 3,
            # the semantics of map has changed (why, oh why???) and the check
            # for the length becomes necessary...
            # type error: Item "None" of "Union[None, Attr, Comment, Document, DocumentFragment, DocumentType, Element, Entity, Notation, ProcessingInstruction, Text]" has no attribute "childNodes"
            if len(node.childNodes) != len(other.childNodes):  # type: ignore[union-attr]
                return False
            # type error: Item "None" of "Union[None, Attr, Comment, Document, DocumentFragment, DocumentType, Element, Entity, Notation, ProcessingInstruction, Text]" has no attribute "childNodes"
            for nc, oc in map(lambda x, y: (x, y), node.childNodes, other.childNodes):  # type: ignore[union-attr]
                if not _isEqualXMLNode(nc, oc):
                    return False
            # if we got here then everything is fine:
            return True

        if node is None or other is None:
            return False

        if node.nodeType != other.nodeType:
            return False

        if node.nodeType in [XMLNode.DOCUMENT_NODE, XMLNode.DOCUMENT_FRAGMENT_NODE]:
            return recurse()

        elif node.nodeType == XMLNode.ELEMENT_NODE:
            if TYPE_CHECKING:
                assert isinstance(node, xml.dom.minidom.Element)
                assert isinstance(other, xml.dom.minidom.Element)
            # Get the basics right
            if not (
                node.tagName == other.tagName and node.namespaceURI == other.namespaceURI
            ):
                return False

            # Handle the (namespaced) attributes; the namespace setting key
            # should be ignored, though
            # Note that the minidom orders the keys already, so we do not have
            # to worry about that, which is a bonus...
            n_keys = [
                k
                for k in node.attributes.keysNS()
                if k[0] != "http://www.w3.org/2000/xmlns/"
            ]
            o_keys = [
                k
                for k in other.attributes.keysNS()
                if k[0] != "http://www.w3.org/2000/xmlns/"
            ]
            if len(n_keys) != len(o_keys):
                return False
            for k in n_keys:
                if not (
                    k in o_keys
                    and node.getAttributeNS(k[0], k[1]) == other.getAttributeNS(k[0], k[1])
                ):
                    return False

            # if we got here, the attributes are all right, we can go down
            # the tree recursively
            return recurse()

        elif node.nodeType in [
            XMLNode.TEXT_NODE,
            XMLNode.COMMENT_NODE,
            XMLNode.CDATA_SECTION_NODE,
            XMLNode.NOTATION_NODE,
        ]:
            if TYPE_CHECKING:
                assert isinstance(
                    node,
                    (
                        xml.dom.minidom.Text,
                        xml.dom.minidom.Comment,
                        xml.dom.minidom.CDATASection,
                        xml.dom.minidom.Notation,
                    ),
                )
                assert isinstance(
                    other,
                    (
                        xml.dom.minidom.Text,
                        xml.dom.minidom.Comment,
                        xml.dom.minidom.CDATASection,
                        xml.dom.minidom.Notation,
                    ),
                )
            # type error: Item "Notation" of "Union[Comment, Document, Notation, Text]" has no attribute "data"
            return node.data == other.data  # type: ignore[union-attr] # FIXME

        elif node.nodeType == XMLNode.PROCESSING_INSTRUCTION_NODE:
            if TYPE_CHECKING:
                assert isinstance(node, xml.dom.minidom.ProcessingInstruction)
                assert isinstance(other, xml.dom.minidom.ProcessingInstruction)
            return node.data == other.data and node.target == other.target

        elif node.nodeType == XMLNode.ENTITY_NODE:
            return node.nodeValue == other.nodeValue

        elif node.nodeType == XMLNode.DOCUMENT_TYPE_NODE:
            if TYPE_CHECKING:
                assert isinstance(node, xml.dom.minidom.DocumentType)
                assert isinstance(other, xml.dom.minidom.DocumentType)
            return node.publicId == other.publicId and node.systemId == other.systemId

        else:
            # should not happen, in fact
            raise Exception(f"I dont know how to compare XML Node type: {node.nodeType}")