#NEWLINE# def _next_controller_changed( self , old , new ) : #NEWLINE# #INDENT# ' Called when the next controller is changed. ' #NEWLINE# if ( old is not None ) : #NEWLINE# #INDENT# old . on_trait_change ( self . _on_controller_complete , 'complete' , remove = True ) #NEWLINE# #UNINDENT# if ( new is not None ) : #NEWLINE# #INDENT# new . on_trait_change ( self . _on_controller_complete , 'complete' ) #NEWLINE# #UNINDENT# self . _update ( ) #NEWLINE# return