def GetFileObject(self, data_stream_name=''):
    """Retrieves the file-like object.

    Args:
      data_stream_name (Optional[str]): name of the data stream, where an empty
          string represents the default data stream.

    Returns:
      FileIO: a file-like object or None if not available.
    """
    if data_stream_name:
      return None

    return resolver.Resolver.OpenFileObject(
        self.path_spec, resolver_context=self._resolver_context)
Retrieves the file-like object.

    Args:
      data_stream_name (Optional[str]): name of the data stream, where an empty
          string represents the default data stream.

    Returns:
      FileIO: a file-like object or None if not available.