docs: def add(self, *tokens: str) -> None:
          """Add new tokens to list."""
          from wdom.web_node import WdomElement
          _new_tokens = []
          for token in tokens:
              self._validate_token(token)
              if token and token not in self:
                  self._list.append(token)
                  _new_tokens.append(token)
          if isinstance(self._owner, WdomElement) and _new_tokens:
              self._owner.js_exec('addClass', _new_tokens)