# Source code for prov.graph

    import networkx as nx
    from prov.model import (
        ProvDocument,
        ProvRecord,
        ProvElement,
        ProvEntity,
        ProvActivity,
        ProvAgent,
        ProvRelation,
        PROV_ATTR_ENTITY,
        PROV_ATTR_ACTIVITY,
        PROV_ATTR_AGENT,
        PROV_ATTR_TRIGGER,
        PROV_ATTR_GENERATED_ENTITY,
        PROV_ATTR_USED_ENTITY,
        PROV_ATTR_DELEGATE,
        PROV_ATTR_RESPONSIBLE,
        PROV_ATTR_SPECIFIC_ENTITY,
        PROV_ATTR_GENERAL_ENTITY,
        PROV_ATTR_ALTERNATE1,
        PROV_ATTR_ALTERNATE2,
        PROV_ATTR_COLLECTION,
        PROV_ATTR_INFORMED,
        PROV_ATTR_INFORMANT,
        PROV_ATTR_BUNDLE,
        PROV_ATTR_PLAN,
        PROV_ATTR_ENDER,
        PROV_ATTR_STARTER,
        ProvBundle,
    )

    __author__ = "Trung Dong Huynh"
    __email__ = "trungdong@donggiang.com"

    INFERRED_ELEMENT_CLASS = {
        PROV_ATTR_ENTITY: ProvEntity,
        PROV_ATTR_ACTIVITY: ProvActivity,
        PROV_ATTR_AGENT: ProvAgent,
        PROV_ATTR_TRIGGER: ProvEntity,
        PROV_ATTR_GENERATED_ENTITY: ProvEntity,
        PROV_ATTR_USED_ENTITY: ProvEntity,
        PROV_ATTR_DELEGATE: ProvAgent,
        PROV_ATTR_RESPONSIBLE: ProvAgent,
        PROV_ATTR_SPECIFIC_ENTITY: ProvEntity,
        PROV_ATTR_GENERAL_ENTITY: ProvEntity,
        PROV_ATTR_ALTERNATE1: ProvEntity,
        PROV_ATTR_ALTERNATE2: ProvEntity,
        PROV_ATTR_COLLECTION: ProvEntity,
        PROV_ATTR_INFORMED: ProvActivity,
        PROV_ATTR_INFORMANT: ProvActivity,
        PROV_ATTR_BUNDLE: ProvBundle,
        PROV_ATTR_PLAN: ProvEntity,
        PROV_ATTR_ENDER: ProvEntity,
        PROV_ATTR_STARTER: ProvEntity,
    }

    def prov_to_graph(prov_document):
        """
        Convert a :class:`~prov.model.ProvDocument` to a `MultiDiGraph
        <https://networkx.github.io/documentation/stable/reference/classes/multidigraph.html>`_
        instance of the `NetworkX <https://networkx.github.io/>`_ library.

        :param prov_document: The :class:`~prov.model.ProvDocument` instance to convert.
        """
        g = nx.MultiDiGraph()
        unified = prov_document.unified()
        node_map = dict()
        for element in unified.get_records(ProvElement):
            g.add_node(element)
            node_map[element.identifier] = element

        for relation in unified.get_records(ProvRelation):
            # taking the first two elements of a relation
            attr_pair_1, attr_pair_2 = relation.formal_attributes[:2]
            # only need the QualifiedName (i.e. the value of the attribute)
            qn1, qn2 = attr_pair_1[1], attr_pair_2[1]
            if qn1 and qn2:  # only proceed if both ends of the relation exist
                try:
                    if qn1 not in node_map:
                        node_map[qn1] = INFERRED_ELEMENT_CLASS[attr_pair_1[0]](None, qn1)
                    if qn2 not in node_map:
                        node_map[qn2] = INFERRED_ELEMENT_CLASS[attr_pair_2[0]](None, qn2)
                except KeyError:
                    # Unsupported attribute; cannot infer the type of the element
                    continue  # skipping this relation
                g.add_edge(node_map[qn1], node_map[qn2], relation=relation)
        return g

    def graph_to_prov(g):
        """
        Convert a `MultiDiGraph
        <https://networkx.github.io/documentation/stable/reference/classes/multidigraph.html>`_
        that was previously produced by :func:`prov_to_graph` back to a
        :class:`~prov.model.ProvDocument`.

        :param g: The graph instance to convert.
        """
        prov_doc = ProvDocument()
        for n in g.nodes():
            if isinstance(n, ProvRecord) and n.bundle is not None:
                prov_doc.add_record(n)
        for _, _, edge_data in g.edges(data=True):
            try:
                relation = edge_data["relation"]
                if isinstance(relation, ProvRecord):
                    prov_doc.add_record(relation)
            except KeyError:
                pass

        return prov_doc