# Source code for opentelemetry.sdk.metrics._internal.exemplar.exemplar

    # Copyright The OpenTelemetry Authors
    #
    # Licensed under the Apache License, Version 2.0 (the "License");
    # you may not use this file except in compliance with the License.
    # You may obtain a copy of the License at
    #
    #     http://www.apache.org/licenses/LICENSE-2.0
    #
    # Unless required by applicable law or agreed to in writing, software
    # distributed under the License is distributed on an "AS IS" BASIS,
    # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    # See the License for the specific language governing permissions and
    # limitations under the License.

    import dataclasses
    from typing import Optional, Union

    from opentelemetry.util.types import Attributes

    @dataclasses.dataclass(frozen=True)
    class Exemplar:
        """A representation of an exemplar, which is a sample input measurement.

        Exemplars also hold information about the environment when the measurement
        was recorded, for example the span and trace ID of the active span when the
        exemplar was recorded.

        Attributes
            trace_id: (optional) The trace associated with a recording
            span_id: (optional) The span associated with a recording
            time_unix_nano: The time of the observation
            value: The recorded value
            filtered_attributes: A set of filtered attributes which provide additional insight into the Context when the observation was made.

        References:
            https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/data-model.md#exemplars
            https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#exemplar
        """

        # TODO Fix doc - if using valid Google `Attributes:` key, the attributes are duplicated
        # one will come from napoleon extension and the other from autodoc extension. This
        # will raise an sphinx error of duplicated object description
        # See https://github.com/sphinx-doc/sphinx/issues/8664

        filtered_attributes: Attributes
        value: Union[int, float]
        time_unix_nano: int
        span_id: Optional[int] = None
        trace_id: Optional[int] = None