#NEWLINE# def add_resource( self , resource , parents = [ ] ) : #NEWLINE# #INDENT# 'Add a resource or append parents resources to a special resource.\n\n        All added resources should be hashable.\n        (http://docs.python.org/glossary.html#term-hashable)\n        ' #NEWLINE# self . _resources . setdefault ( resource , set ( ) ) #NEWLINE# self . _resources [ resource ] . update ( parents )