Load the submission from a file-like object

        :param fileobj: File-like object
        :return: the loaded submission

def load(fileobj):
        """Load the submission from a file-like object

        :param fileobj: File-like object
        :return: the loaded submission
        """
        with gzip.GzipFile(fileobj=fileobj, mode='r') as z:
            submission = Submission(metadata=json.loads(z.readline()))

            for line in z:
                token_id, token = json.loads(line)
                submission['tokens'][token_id] = token

        return submission