#NEWLINE# def unsubscribe( self , client_id , topic ) : #NEWLINE# #INDENT# ' Unsubscribe from a topic\n\n        Keyword arguments:\n        client_id -- the ID of the client to unsubscribe\n        topic     -- the topic to unsubscribe from\n\n        ' #NEWLINE# if ( not ( topic in self . _subscribers ) ) : #NEWLINE# #INDENT# return #NEWLINE# #UNINDENT# self . _subscribers [ topic ] . unsubscribe ( client_id ) #NEWLINE# if ( not self . _subscribers [ topic ] . has_subscribers ( ) ) : #NEWLINE# #INDENT# self . _subscribers [ topic ] . unregister ( ) #NEWLINE# del client_id . _subscribers [ topic ]