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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 handle_receive( request: RequestType, user: UserType = None, sender_key_fetcher: Callable[[str], str] = None, skip_author_verification: bool = False ) -> Tuple[str, str, List]: """Takes a request and passes it to the correct protocol. Returns a tuple of: - sender id - protocol name - list of entities NOTE! The returned sender is NOT necessarily the *author* of the entity. By sender here we're talking about the sender of the *request*. If this object is being relayed by the sender, the author could actually be a different identity. :arg request: Request object of type RequestType - note not a HTTP request even though the structure is similar :arg user: User that will be passed to `protocol.receive` (only required on private encrypted content) MUST have a `private_key` and `id` if given. :arg sender_key_fetcher: Function that accepts sender handle and returns public key (optional) :arg skip_author_verification: Don't verify sender (test purposes, false default) :returns: Tuple of sender id, protocol name and list of entity objects """

    logger.debug("handle_receive: processing request: %s", request)
    found_protocol = identify_protocol_by_request(request)

    logger.debug("handle_receive: using protocol %s", found_protocol.PROTOCOL_NAME)
    protocol = found_protocol.Protocol()
    sender, message = protocol.receive(
        request, user, sender_key_fetcher, skip_author_verification=skip_author_verification)
    logger.debug("handle_receive: sender %s, message %s", sender, message)

    mappers = importlib.import_module("federation.entities.%s.mappers" % found_protocol.PROTOCOL_NAME)
    entities = mappers.message_to_objects(message, sender, sender_key_fetcher, user)
    logger.debug("handle_receive: entities %s", entities)

    return sender, found_protocol.PROTOCOL_NAME, entities