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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 receive( self, request: RequestType, user: UserType = None, sender_key_fetcher: Callable[[str], str] = None, skip_author_verification: bool = False) -> Tuple[str, dict]: """ Receive a request. For testing purposes, `skip_author_verification` can be passed. Authorship will not be verified. """

        self.user = user
        self.get_contact_key = sender_key_fetcher
        self.payload = json.loads(decode_if_bytes(request.body))
        self.request = request
        self.extract_actor()
        # Verify the message is from who it claims to be
        if not skip_author_verification:
            self.verify_signature()
        return self.actor, self.payload