code: def set_mode_rtl(self):
          '''enter RTL mode'''
          if self.mavlink10():
              self.mav.command_long_send(self.target_system, self.target_component,
                                         mavlink.MAV_CMD_NAV_RETURN_TO_LAUNCH, 0, 0, 0, 0, 0, 0, 0, 0)
          else:
              MAV_ACTION_RETURN = 3
              self.mav.action_send(self.target_system, self.target_component, MAV_ACTION_RETURNf set_mode_rtl(self):
          '''enter RTL mode'''
          if self.mavlink10():
              self.mav.command_long_send(self.target_system, self.target_component,
                                         mavlink.MAV_CMD_NAV_RETURN_TO_LAUNCH, 0, 0, 0, 0, 0, 0, 0, 0)
          else:
              MAV_ACTION_RETURN = 3
              self.mav.action_send(self.target_system, self.target_component, MAV_ACTION_RETURN)
docs: enter RTL mode