Cannot convert method group expression to IEnumerator

I want my game to wait for seconds before spawning a new enemy. I am receiving two errors which i do not understand why I am receiving them Please help me if you can.

First Error

The best overloaded method match for 'StartCoroutine(IEnumerator) has some invalid arguments. (on line 3)

But from what I can see it does not have invalid arguments

My Spawner class

 void Start()
     {
         StartCoroutine(WaitBeforeSpawning);
     }
 
     public IEnumerator WaitBeforeSpawning()
     {
         yield return StartCoroutine(MyCoroutine.WaitForRealSeconds(1.3f));
         RepositionEnemy();
     }

Static Coroutine Class Note that the method takes a float as an arg

 public static class MyCoroutine
 {
     public static IEnumerator WaitForRealSeconds(float time)
     {
         float start = Time.realtimeSinceStartup;
 
         while(Time.realtimeSinceStartup < (start + time))
         {
             yield return null;
         }
     }
 }

Second Error

Argument `#1' cannot convert method group expression to type System.Collections.IEnumerator'

...I am not trying to convert anything here i am just calling a method from another class, why does it say this?

Collector class error comes from

 public EnemySpawner enemySpawnerScript;
 
     void Awake(){
         enemySpawnerScript = GameObject.FindObjectOfType (typeof(EnemySpawner)) as EnemySpawner;
 
     }

     public void SpawnEnemy()
     {
         StartCoroutine(enemySpawnerScript.WaitBeforeSpawning());
     }