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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_result(self, *, backend=None, block=False, timeout=None):
 """Get the result associated with this message from a result backend. Warning: If you use multiple result backends or brokers you should always pass the backend parameter. This method is only able to infer the result backend off of the default broker. Parameters: backend(ResultBackend):
 The result backend to use to get the result. If omitted, this method will try to find and use the result backend on the default broker instance. block(bool):
 Whether or not to block while waiting for a result. timeout(int):
 The maximum amount of time, in ms, to block while waiting for a result. Raises: RuntimeError: If there is no result backend on the default broker. ResultMissing: When block is False and the result isn't set. ResultTimeout: When waiting for a result times out. Returns: object: The result. """

        if not backend:
            broker = get_broker()
            for middleware in broker.middleware:
                if isinstance(middleware, Results):
                    backend = middleware.backend
                    break
            else:
                raise RuntimeError("The default broker doesn't have a results backend.")

        return backend.get_result(self, block=block, timeout=timeout)