docs: def _getel(key, value):
      """Returns an element given a key and value."""
      if key in ['HorizontalRule', 'Null']:
          return elt(key, 0)()
      elif key in ['Plain', 'Para', 'BlockQuote', 'BulletList',
                   'DefinitionList', 'HorizontalRule', 'Null']:
          return elt(key, 1)(value)
      return elt(key, len(value))(*value)