code: def GetFileObject(self, data_stream_name=''):
      
      if not self.IsFile():
        raise IOError('Cannot open non-file.')
  
      if data_stream_name:
        return None
  
      location = getattr(self.path_spec, 'location', None)
      if location is None:
        return None
  
      file_data = self._file_system.GetDataByPath(location)
      file_object = fake_file_io.FakeFile(self._resolver_context, file_data)
      file_object.open(path_spec=self.path_spec)
      return file_object
docs: 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:
        FakeFileIO: a file-like object or None if not available.
  
      Raises:
        IOError: if the file entry is not a file.
        OSError: if the file entry is not a file.