#NEWLINE# def once( signals , callback = None ) : #NEWLINE# #INDENT# '\n    Registers a callback that will respond to an event at most one time\n\n    :param signals: A single signal or list/tuple of signals that callback should respond to\n    :param callback: A callable that should repond to supplied signal(s)\n    ' #NEWLINE# return on ( callback , callback , max_calls = 1 )