code: def send_email_confirmation_instructions(self, user):
          
          token = self.security_utils_service.generate_confirmation_token(user)
          confirmation_link = url_for('security_controller.confirm_email',
                                      token=token, _external=True)
          self.send_mail(
              _('flask_unchained.bundles.security:email_subject.email_confirmation_instructions'),
              to=user.email,
              template='security/email/email_confirmation_instructions.html',
              user=user,
              confirmation_link=confirmation_link)
          confirm_instructions_sent.send(app._get_current_object(), user=user,
                                         token=token)
docs: Sends the confirmation instructions email for the specified user.
  
          Sends signal `confirm_instructions_sent`.
  
          :param user: The user to send the instructions to.