code: def do_s2(self, line):
          
          self.application.send_select_and_operate_command_set(opendnp3.CommandSet(
              [
                  opendnp3.WithIndex(opendnp3.ControlRelayOutputBlock(opendnp3.ControlCode.LATCH_ON), 0)
              ]),
              command_callback
          )
docs: Send a SelectAndOperate BinaryOutput (group 12) CommandSet to the Outstation. Command syntax is: s2