def unregister_engine(self, engine_or_name):

        engines = self.engines
        name = None
        if isinstance(engine_or_name, str):
            name = engine_or_name
        else:
            for key, engine in engines.items():
                if engine_or_name == engine:
                    name = key
                    break

        if name:
            del engines[name]
        logger.debug('Engine named %s unregistered', name)
Establish that the _disassoc method returns an unchanged status
dataset/ETHPy150Open enthought/mayavi/mayavi/core/registry.py/Registry.unregister_engine--crossover with--dataset/ETHPy150Open ansible/tower-cli/tests/test_models_base.py/ResourceTests.test_disassoc_not_already_present