有麻烦。找不到我把事情搞砸的地方。如果有人能发现这个问题，我将不胜感激。错误是：error CS1031:Type expected我尝试在脚本上运行Unity调试，但没有成功。我真的不觉得有什么问题。

'''
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;

public class AiStateMachine : 
{
    public AiState[] states;
    public AiAgent agent;
    public AiStateId currentState; 

    public AiStateMachine(AiAgent agent)
    {
        this.agent = agent;
        int numStates = System.Enum.Getnames(typeof(AiStateId)).Length;
        states = new AiState[numStates];

    }

    public void RegisterState(AiState state)
    {
        int index = (int)state.GetId();
        states[index] = state;
    }

    public AIStateMachine GetState(AiStateId stateId) 
    {
        int index = (int)stateId;
        return states[index];
    }

    public void Update() 
    {
        GetState(currentState)?.Update(agent);

    }

    public void ChangeState(AiStateId newState)
    {
        GetState(currentState)?.Exit(agent);
        currentState = newState;
        GetState(currentState)?.Enter(agent); 
    }
}
'''