#NEWLINE# def add_dependency( self , obj , depending_on ) : #NEWLINE# #INDENT# ng = self . g . copy ( ) #NEWLINE# ng . add_edge ( obj , ng ) #NEWLINE# if ( not is_directed_acyclic_graph ( ng ) ) : #NEWLINE# #INDENT# raise ValueError ( 'Adding a dependency of {} on {} introduces a dependency cycle!.' . format ( obj , depending_on ) ) #NEWLINE# #UNINDENT# self . g = ng