code: def send(self, envelope):
          
          rejected = self.conn.sendmail(
              stringify_address(envelope.sender),
              [stringify_address(k) for k in envelope.receivers],
              envelope.string(),
          )
          status_code, reason = self.conn.noop()
          return SendmailResponse(
              status_code,
              reason,
              rejected,
          )
docs: Send an *envelope* which may be an envelope
          or an enclosure-like object, see
          :class:`~mailthon.enclosure.Enclosure` and
          :class:`~mailthon.envelope.Envelope`, and
          returns a :class:`~mailthon.response.SendmailResponse`
          object.