def set_tempo(ticks: int=4, bpm: int=120) ->None:
    """
    Sets the approximate tempo for playback.

    A number of ticks (expressed as an integer) constitute a beat.
    Each beat is to be played at a certain frequency per minute
    (expressed as the more familiar BPM - beats per minute -
     also as an integer).

    Suggested default values allow the following useful behaviour:

        music.set_tempo() - reset the tempo to default of ticks = 4, bpm = 120
        music.set_tempo(ticks=8) - change the “definition” of a beat
        music.set_tempo(bpm=180) - just change the tempo

    To work out the length of a tick in milliseconds is very simple arithmetic:
    60000/bpm/ticks_per_beat . For the default values that’s
    60000/120/4 = 125 milliseconds or 1 beat = 500 milliseconds.
    """
