'and "requires_system_checks", which is illegal. Use only "requires_system_checks".', replace '%s' for self.__class__.__name__. call the method self.requires_system_checks with an argument: self.requires_system_checks if has_new_option is true,
self . requires_system_checks = ( self . requires_system_checks if has_new_option else self . requires_model_validation if has_old_option else True )