code: def send_invite_user_email(self, user, user_invitation):
          
  
          # Verify config settings
          if not self.user_manager.USER_ENABLE_EMAIL: return
          if not self.user_manager.USER_ENABLE_INVITE_USER: return
  
          # The user param points to the inviter
          # The user_invitation param points to the invitee
          invited_by_user = user
  
          # Use the invitation email
          email = user_invitation.email
  
          # Create a dummy user object to an empty name for the invitee
          user = self.user_manager.db_manager.UserClass(email=email)
  
          # Generate a accept_invitation_link
          token = self.user_manager.generate_token(user_invitation.id)
          accept_invitation_link = url_for('user.register', token=token, _external=True)
  
          # Render email from templates and send it via the configured EmailAdapter
          self._render_and_send_email(
              email,
              user,
              self.user_manager.USER_INVITE_USER_EMAIL_TEMPLATE,
              accept_invitation_link=accept_invitation_link,
              invited_by_user=invited_by_user,
          )
docs: Send the 'user invitation' email.