code: def send_message(self,
                       subject_or_message: Optional[Union[Message, str]] = None,
                       to: Optional[Union[str, List[str]]] = None,
                       **kwargs):
          
          to = to or kwargs.pop('recipients', [])
          return self.send(subject_or_message, to, **kwargs)
docs: Send an email using the send function as configured by
          :attr:`~flask_unchained.bundles.mail.config.Config.MAIL_SEND_FN`.
  
          :param subject_or_message: The subject line, or an instance of
                                     :class:`flask_mail.Message`.
          :param to: The message recipient(s).
          :param kwargs: Extra values to pass on to :class:`~flask_mail.Message`