code: def GetDisplayName(self, file_entry=None):
      
      if file_entry is None:
        file_entry = self._file_entry
  
      if file_entry is None:
        raise ValueError('Missing file entry')
  
      path_spec = getattr(file_entry, 'path_spec', None)
  
      relative_path = path_helper.PathHelper.GetRelativePathForPathSpec(
          path_spec, mount_path=self._mount_path)
      if not relative_path:
        return file_entry.name
  
      return self.GetDisplayNameForPathSpec(path_spec)
docs: Retrieves the display name for a file entry.
  
      Args:
        file_entry (Optional[dfvfs.FileEntry]): file entry object, where None
            will return the display name of self._file_entry.
  
      Returns:
        str: human readable string that describes the path to the file entry.
  
      Raises:
        ValueError: if the file entry is missing.