#NEWLINE# def remove_listener( self , listener ) : #NEWLINE# #INDENT# 'Unregister some listener; ignore if the listener was never\n        registered.\n\n        :type listener: :class:`SessionListener`\n        ' #NEWLINE# logger . debug ( ( 'discarding listener %r' % listener ) ) #NEWLINE# with listener . _lock : #NEWLINE# #INDENT# self . _listeners . discard ( listener )