def METHOD_NAME(self, name, mode):
    if 'w' in mode or '+' in mode or 'a' in mode:
        raise ValueError(
            'FiletrackerStorage.open does not support '
            'writing. Use FiletrackerStorage.save.'
        )
    path = self._make_filetracker_path(name)
    reader, _version = self.client.get_stream(path)
    return File(reader, FiletrackerFilename(name))