langgraph---条件边

（1）使用langgrahp.rpebuilt中的tools_condition

from langgraph.prebuilt import tools_condition

builder.add_conditional_edges('llm节点',tools_condition)

（2）自定义 条件边

#（1）自定义路由函数
def rout_func(state:State):

    if hasattr(state,'messages'):
        messages = state.messages
    elif isinstance(state,dict) and 'messages' in state:
        messages = state.get('messages', [])
    else:
        raise ValueError(f"无法从状态中获取到messages:{state}")

    last_message = messages[-1]

    if hasattr(last_message,'tool_calls') and len(last_message.tool_calls)>0:
        return 'tools'

#（2）条件边
builder.add_conditional_edges(
    'llm节点',
    rout_func,
    path_map={
        'tools':'tools',
        END:END
    }
)