code: def send_message(self, sender, um_to_user_list, body):
          
          msg = self.model(sender=sender,
                           body=body)
          msg.save()
  
          # Save the recipients
          msg.save_recipients(um_to_user_list)
          msg.update_contacts(um_to_user_list)
          signals.email_sent.send(sender=None,msg=msg)
  
          return msg
docs: Send a message from a user, to a user.
  
          :param sender:
              The :class:`User` which sends the message.
  
          :param um_to_user_list:
              A list which elements are :class:`User` to whom the message is for.
  
          :param message:
              String containing the message.