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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 is_elem_ref(elem_ref):
 """ Returns true if the elem_ref is an element reference :param elem_ref: :return: """

    return (
        elem_ref
        and isinstance(elem_ref, tuple)
        and len(elem_ref) == 3
        and (elem_ref[0] == ElemRefObj or elem_ref[0] == ElemRefArr)
    )