#NEWLINE# def symmetric_difference( self , case_set ) : #NEWLINE# #INDENT# 'Return a new CaseSet with Cases in either this one or the other but\n        not both.\n        ' #NEWLINE# self . _check_compatability ( case_set ) #NEWLINE# return self . _make_case_set ( self . _tupset . symmetric_difference ( case_set . _tupset ) )