code: def send(self, to, subject, body, reply_to=None, **kwargs):
          
          if self.provider == "SES":
              self.mail.send(to=to,
                             subject=subject,
                             body=body,
                             reply_to=reply_to,
                             **kwargs)
          elif self.provider == "FLASK-MAIL":
              msg = flask_mail.Message(recipients=to, subject=subject, body=body, reply_to=reply_to,
                                       sender=self.app.config.get("MAIL_DEFAULT_SENDER"))
              self.mail.send(msg)
docs: Send simple message