Keyboard in IOS

This feels like a question that should be out there somewhere, but I have not been able to find anything helpful about how to use ios keyboards. Unity scripting said:

 TouchScreenKeyboard.Open("", TouchScreenKeyboardType.Default, false, false, true, true);

But in my code:

 using UnityEngine;
 using System.Collections;
 
 public class touchKB : MonoBehaviour {
 
 
 
     void OnMouseDown(){
     
         Debug.Log ("hi");
         TouchScreenKeyboard.Open ("", TouchScreenKeyboardType.Default, false, false, true, true);
 
     }
 
 }

I get input from debug.log, but I don't see the keyboard pop up. How do you get the ios keyboard to appear? Thanks for the help.