docs: def _molfile(stream):
      """Process ``Molfile``.
      
      :param stream: Queue containing lines of text.
      :type stream: :py:class:`collections.deque`
      :return: Tuples of data.
      """
      yield MolfileStart()
      yield HeaderBlock(stream.popleft().strip(), stream.popleft().strip(), stream.popleft().strip())
      # yield from _ctab(stream)
      for token in _ctab(stream):
          yield token
      yield MolfileEnd()