# This one decides what to do


class Engine(object):
    
    def __enter__(self):
        pass

    def __exit__(self, exc_type, exc_val, exc_tb):
        pass

# This one decides what to do


class Engine(object):

    def __enter__(self):
        pass

    def __exit__(self, exc_type, exc_val, exc_tb):
        pass

Add engine frame