IEnumerator keeps saying not all code paths return values

on the IEnumerator hitting Its saying not all code paths return a value I’m so confused I’m doing the same as everyone else please tell me what I did wrong!!!

public class BasicAI : MonoBehaviour {

private NavMeshAgent agent;
private Animator Animator;

public float Health = 200;
public float DistanceToHit;
public float Damage;

public bool Chase;
private bool IsChasing;
public bool Wander;
public bool PickWander;
public bool Dead = false;
public bool CanHit = false;
public bool Touching = false;
public bool Hit = false;
public bool hitting = true;

private Transform PlayerTransform;
public Transform WanderRight;
public Transform WanderLeft;
public Transform WanderForward;
public Transform WanderBackward;
public Transform WanderStay;
public Transform WanderPlace;
private float HowFarFromPlayer;

// Use this for initialization
void Start () {
    Animator = GetComponent<Animator>();
    agent = GetComponent<NavMeshAgent>();
}
private void OnCollisionStay(Collision collision)
{
    if (collision.collider.GetComponent<Player>())
    {
        if (Dead == false)
        {
            collision.collider.GetComponent<Player>().health -= 20;
            Touching = true;
            CanHit = true;
        }
    }
}
private void OnCollisionExit(Collision collision)
{
    if (collision.collider.GetComponent<Player>())
    {
        Touching = false;
        CanHit = false;
    }
}
private void OnTriggerEnter(Collider target)
{
    if (target.GetComponent<Player>())
    {
        PlayerTransform = target.transform;
        IsChasing = true;
        
    }
}
private void OnTriggerExit(Collider target)
{
    if (target.GetComponent<Player>())
    {
        PlayerTransform = null;
        IsChasing = false;
    }
}

IEnumerator Hitting()
{

}
void Update () {
    Animator.SetBool("Walk", IsChasing);
    Animator.SetBool("Die", Dead);
    if (PlayerTransform != null)
    {
        HowFarFromPlayer = Vector3.Distance(gameObject.transform.position, PlayerTransform.transform.position);
    }
    //Health Die 
    if(Hit == true)
    {
        hitting = true;
        StartCoroutine(Hitting());
    }
    if (IsChasing == true)
    {
       
            if (HowFarFromPlayer <= DistanceToHit)
            {
                Hit = true;
            }
        
    }
    if (Health <= 0)
    {
        IsChasing = false;
        Dead = true;
        agent.SetDestination(gameObject.transform.position);
        Destroy(gameObject,3);
    }
    if(IsChasing == false)
    {
        agent.SetDestination(gameObject.transform.position);
    }
    if(IsChasing == true)
    {
        agent.SetDestination(PlayerTransform.transform.position);
    }
}

}

The error is pretty clear isn’t it? Your IEnumerator needs to return something. It’s almost as having a function that needs to return an int for example (but not really).

Read this again: