def recover(self, transport):
    """Recover from a failure.

    This method should be used when a :class:`ResumableUpload` is in an
    :attr:`~ResumableUpload.invalid` state due to a request failure.

    This will verify the progress with the server and make sure the
    current upload is in a valid state before :meth:`transmit_next_chunk`
    can be used again.

    Args:
        transport (~requests.Session): A ``requests`` object which can
            make authenticated requests.

    Returns:
        ~requests.Response: The HTTP response returned by ``transport``.
    """
    method, url, payload, headers = self._prepare_recover_request()
    # NOTE: We assume "payload is None" but pass it along anyway.
    result = _helpers.http_request(
        transport, method, url, data=payload, headers=headers,
        retry_strategy=self._retry_strategy)
    self._process_recover_response(result)
    return result