'Returns the number of renderable events'

def renderable_events(self, date, hour):

    renderable_events = []
    for event in self.events:
        if event.covers(date, hour):
            renderable_events.append(event)
    if hour:
        for current in renderable_events:
            for event in self.events:
                if (event not in renderable_events):
                    for hour in range(self.start_hour, self.end_hour):
                        if (current.covers(date, hour) and event.covers(date, hour)):
                            renderable_events.append(event)
                            break
    return renderable_events
