<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def endpoint(self, endpoint: str) -> Callable: """Add an endpoint to the blueprint. This is designed to be used as a decorator, and has the same arguments as :meth:`~quart.Quart.endpoint`. An example usage, .. code-block:: python blueprint = Blueprint(__name__) @blueprint.endpoint('index') def index():
 """

        def decorator(func: Callable) -> Callable:
            self.record_once(lambda state: state.register_endpoint(endpoint, func))
            return func
        return decorator