#NEWLINE# def is_relevant_system( self , var_of_interest , system ) : #NEWLINE# #INDENT# '\n        Args\n        ----\n        var_of_interest : str\n            Name of a variable of interest (either a parameter or a constraint\n            or objective output, depending on mode.)\n\n        system : `System`\n            The system being checked for relevant w.r.t. the variable of\n            interest.\n\n        Returns\n        -------\n        bool\n            True if the given system is relevant for the given variable of\n            interest.\n        ' #NEWLINE# return ( ( var_of_interest is None ) or ( system . pathname in self . _relevant_systems [ var_of_interest ] ) )