def keyEvent(a):
    """Create key for an event

    :param a: First event
    """
    a = a['DTSTART'].dt
    if getattr(a, 'date', None):
        a_date = a.date()
        a = a.hour, a.minute
    else:
        a_date = a
        a = 0, 0
    return a_date, a
