(Unity)複数の子供を取得して動的にコンポーネントを付加する(AddComponent)

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

public class TankHealth : MonoBehaviour
{
    public GameObject effectPrefab1;
    public GameObject effectPrefab2;
    public int tankHP;

    private void OnCollisionEnter(Collision collision)
    {
        if (collision.gameObject.tag == "EnemyShell")
        {
            tankHP -= 1;
            Destroy(collision.gameObject);

            if (tankHP > 0)
            {
                GameObject effect1 = Instantiate(effectPrefab1, transform.position, Quaternion.identity);
                Destroy(effect1, 1.0f);  
            }
            else
            {
                GameObject effect2 = Instantiate(effectPrefab2, transform.position, Quaternion.identity);
                Destroy(effect2, 1.0f);

                // (ポイント)
                // Tankの中の全ての子供にRigidbodyを追加する。
                foreach (Transform child in transform)
                {
                    if (child.GetComponent<Rigidbody>() == null)
                    {
                        child.gameObject.AddComponent<BoxCollider>();
                        child.gameObject.AddComponent<Rigidbody>();
                    }
                }
            }
        }
    }
}