#NEWLINE# def undo( self ) : #NEWLINE# #INDENT# 'Undo the last action.\n\n        This will call `undo()` on all controllers involved in this action.\n\n        ' #NEWLINE# controllers = self . back ( ) #NEWLINE# if ( controller is None ) : #NEWLINE# #INDENT# ups = ( ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# ups = tuple ( [ controller . undo ( ) for controller in controllers ] ) #NEWLINE# #UNINDENT# if ( self . process_ups is not None ) : #NEWLINE# #INDENT# return self . process_ups ( ups ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# return ups