code: def _GetSubFileEntries(self):
      
      if self._directory is None:
        self._directory = self._GetDirectory()
  
      zip_file = self._file_system.GetZipFile()
      if self._directory and zip_file:
        for path_spec in self._directory.entries:
          location = getattr(path_spec, 'location', None)
          if location is None:
            continue
  
          kwargs = {}
          try:
            kwargs['zip_info'] = zip_file.getinfo(location[1:])
          except KeyError:
            kwargs['is_virtual'] = True
  
          yield ZipFileEntry(
              self._resolver_context, self._file_system, path_spec, **kwargs)
docs: Retrieves sub file entries.
  
      Yields:
        ZipFileEntry: a sub file entry.