Почему так что не так? програмирование

https://youtu.be/hE162PlVg1k?si=eEoxj_bQzjsScoE7 у него на 6:16 он смог напписать StopMovement, а я не могу скрипт ниже
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Events ;
using UnityEngine.InputSystem;
using Unity.VisualScripting;

public class ControlPlayer : MonoBehaviour
{
public UnityEvent Landed;
public UnityEvent Dead;

[SerializeField] private float _jumpForce;
[SerializeField] private ContactFilter2D _platform;

private Rigidbody2D _rigidbody;
private bool _isOnPlatform => _rigidbody.IsTouching(_platform);

private void Awake()
{
_rigidbody = GetComponent<Rigidbody2D>();
}

public void Jump()
{
if (_isOnPlatform == true)
_rigidbody.AddForce(Vector2.up * _jumpForce, ForceMode2D.Impulse);
}

private void OnCollisionEnter2D(Collision2D collision)
{
GameObject collisionObject = collision.gameObject;

if (collisionObject.transform.parent != null)
{
if (collisionObject.transform.parent.TryGetComponent(out PlatformEffector2D platform))
platform.StopMovement();
}

if (collisionObject.CompareTag("PlatformWall"))
Dead?.Invoke();
else if (collisionObject.CompareTag("Platform"))
{
collisionObject.tag = "Untagged";
Landed?.Invoke();