Invokes `callback` with `args` when the specified event happens.

def on_button(callback, args=(), buttons=(LEFT, MIDDLE, RIGHT, X, X2), types=(UP, DOWN, DOUBLE)):
    """ Invokes `callback` with `args` when the specified event happens. """
    if not isinstance(buttons, (tuple, list)):
        buttons = (buttons,)
    if not isinstance(types, (tuple, list)):
        types = (types,)

    def handler(event):
        if isinstance(event, ButtonEvent):
            if event.event_type in types and event.button in buttons:
                callback(*args)
    _listener.add_handler(handler)
    return handler