我尝试在Unity中为AI编写脚本，但我收到以下错误：错误CS1061：'NavMeshAgent'不包含'setDestination'的定义，而且找不到可接受第一个'NavMeshAgent'型别参数的可存取扩充方法'setDestination'（您是否遗漏using指示词或组件指涉？）

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

public class enemyAI : MonoBehaviour
{
    public NavMeshAgent agent;

    public Transform player;

    public LayerMask whatIsGround, whatIsPlayer;

    // Patrolling
    public Vector3 walkPoint;
    bool walkPointSet;
    public float walkPointRange;

    // Attacking
    public float timeBetweenAttacks;
    bool alreadyAttacked;

    // States
    public float sightRange, attackRange;
    public bool playerInSightRange, playerInAttackRange;

    private void Awake() 
    {
        player = GameObject.Find("player").transform;
        agent = GetComponent<NavMeshAgent>();
    }

    private void Update() 
    {
        // Check for in sight range and in attack range
        playerInSightRange = Physics.CheckSphere(transform.position, sightRange,whatIsPlayer);
        playerInAttackRange = Physics.CheckSphere(transform.position, attackRange, whatIsPlayer);

        if (!playerInSightRange && !playerInAttackRange) Patroling();
        if (playerInSightRange && !playerInAttackRange) ChasePlayer();
        if (playerInSightRange && playerInAttackRange) AttackPlayer();
    }

    private void Patroling() 
    {
        if (!walkPointSet) SearchWalkPoint();

        if (walkPointSet) 
        {
            agent.setDestination(walkPoint);
        }

        Vector3 distanceToWalkPoint = transform.position - walkPoint;

        if (distanceToWalkPoint.magnitude < 1f) 
        {
            walkPointSet = false;
        }
    }

    private void SearchWalkPoint() 
    {
        // Calculate random point in range
        float randomZ = Random.Range(-walkPointRange, walkPointRange);
        float randomX = Random.Range(-walkPointRange, walkPointRange);

        walkPoint = new Vector3(transform.position.x + randomX, transform.position.y, transform.position.z + randomZ);

        if (Physics.Raycast(walkPoint, -transform.up, 2f, whatIsGround)) 
        {
            walkPointSet = true;
        }
    }

    private void ChasePlayer() 
    {
        agent.setDestination(player.position);
    }

    private void AttackPlayer() 
    {
        agent.setDestination(transform.position);
        transform.LookAt(player);

        if (!alreadyAttacked) 
        {
            //AttackCode here
            Debug.Log("Enemy is attacking!!!");


            alreadyAttacked = true;
            Invoke(nameof(ResetAttack), timeBetweenAttacks);

        }
    }

    private void ResetAttack() 
    {
        alreadyAttacked = false;
    }
}

I've gotten 3 errors for the 3 times I use .setDestination(), I don't know what I'm doing wrong...