行为树:如何/何时在叶节点上返回“运行”状态？

class BehaviorNode:
    def tick(self):
        pass

class MoveToNode(BehaviorNode):
    def __init__(self, target_position):
        self.target_position = target_position
        self.current_position = get_current_position()
        self.is_moving = False

    def tick(self):
        if not self.is_moving:
            start_moving_to(self.target_position)
            self.is_moving = True
        
        if is_moving():
            return "运行"
        elif has_reached_target(self.target_position):
            self.is_moving = False
            return "成功"
        else:
            return "失败"

# 使用示例
move_to_node = MoveToNode(target_position=(10, 20))
status = move_to_node.tick()
print(status)  # 输出: 运行