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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_subgraph_by_annotation_value(graph, annotation, values):
 """Induce a sub-graph over all edges whose annotations match the given key and value. :param pybel.BELGraph graph: A BEL graph :param str annotation: The annotation to group by :param values: The value(s) for the annotation :type values: str or iter[str] :return: A subgraph of the original BEL graph :rtype: pybel.BELGraph """

    if isinstance(values, str):
        values = {values}

    return get_subgraph_by_annotations(graph, {annotation: values})