def __init__(self, bpm=None, stop_seconds=60):
# TODO: stop_seconds is nice, but we don't we really want stop_beats or stop_bars
# or something?
assert bpm is not None
self.timeline = Timeline()
self.got_events = False # if we don't get any musical events, the performance will stop
self.stop_seconds = stop_seconds
self.bpm = bpm
# FIXME: this needs to be calculated off of tempo, change to BPM shortly.
self.whole_note_length = ( 60 / 120) * 4
super().__init__()
