How to add randomness in the following code snippet?

How to add randomness in the following line of code (marked with //):

     public GameObject GetPooledObject()
     {
         for (int i = 0; i < pooledObjects.Count; i++)
         {
             if (!pooledObjects[i].activeInHierarchy)
             {
                 return pooledObjects[i];
             }
         }
        
         if (shouldExpand)
         {
             GameObject obj = (GameObject)Instantiate(easySegments[Random.Range(0, easySegments.Count)]);
             obj.SetActive(false);
             pooledObjects.Add(obj);
             return obj;
         }       
         
         return null;
     }
     private void SpawnLevelPart()
     {
         distanceBetween = Random.Range(distanceBetweenMin, distanceBetweenMax);
 
         currentSpawnZ = PlatformDestroyer.comprimento;
 
         transform.position = new Vector3(transform.position.x, transform.position.y, transform.position.z + currentSpawnZ + distanceBetween);
         
         
         GameObject newPlatform;
         newPlatform = GetPooledObject(); // <--------- here
         // like this ---> newPlatform = difficultyLevelPartList[Random.Range(0, difficultyLevelPartList.Count)].GetPooledObject();
 
         newPlatform.transform.position = transform.position;
         newPlatform.transform.rotation = transform.rotation;
         newPlatform.SetActive(true);
     }

When I call this method from another script, it works perfectly, but when it's in the same script, I can't randomize.

I hope you understood my question. Thank you.