def _get_time_signature(e):
    """
    Get the time signature and return

    Returns
    -------
    tuple (mumber, number) OR None
        the tuple is (beats, beat_type). `beats` is the numerator,
        `beat_type` is the denominator of the key signature fraction.
    """

    if e.find('time/beats') is not None and e.find('time/beat-type') is not None:
        beats = int(e.find('time/beats').text)
        beat_type = int(e.find('time/beat-type').text)
        return (beats, beat_type)
    else:
        return None