def message_failure(self):
        """ return a failure message, if one exists """
        if not isinstance(self.main_manifest, Manifest):
            return None
        return self.main_manifest.get('config', 'message_failure', default=None)
def message_failure ( self ) : if not isinstance ( self . main_manifest , Manifest ) : return None return self . main_manifest . get ( 'config' , 'message_failure' , default = None )
return a failure message, if one exists