code: def send_template(self, template, to, reply_to=None, **context):
          
          if self.provider == "SES":
              self.mail.send_template(template=template, to=to, reply_to=reply_to, **context)
          elif self.provider == "FLASK-MAIL":
              ses_mail = ses_mailer.Mail(app=self.app)
              data = ses_mail.parse_template(template=template, **context)
  
              msg = flask_mail.Message(recipients=to,
                                       subject=data["subject"],
                                       body=data["body"],
                                       reply_to=reply_to,
                                       sender=self.app.config.get("MAIL_DEFAULT_SENDER")
                                       )
              self.mail.send(msg)
docs: Send Template message