def open_fileobj(fileobj, mode='rb', compresslevel=9):
    if hasattr(gzip.GzipFile, '__enter__'):
        return gzip.GzipFile(
            filename='', mode=mode, fileobj=fileobj,
            compresslevel=compresslevel
        )
    return GzipFile(
        filename='', mode=mode, fileobj=fileobj, compresslevel=compresslevel
    )