[HELP] UnityEngine.InputSystem not found when class is in namespace

Hello, I'm trying to implement new Unity Input System. I installed new Input System from plugin manager then I created Input Actions and then I generated C# class.
Then I got bunch of errors. The reason was that:

Code (CSharp):

1. using UnityEngine.InputSystem

was not found. Then I investigated and found, that I can get it working when I left C# Class Namespace empty (by default Global namespace)". But then I'm not able to reference it from classes with namespace because

Code (CSharp):

1. global::InputActions

is not working either.
I tried restart everything several times and nothing helped. Once I set the Class Namespace back again, I cannot reference the UnityEngine.InputSystem anymore -> It is not working (not found) from any other class that has namepsace. Once the class has no namepsace the import is working fine.

 

Oh well I found my solution. Since we have an assembly definition for our project, we needed to add a reference to the Unity.InputSystem Assembly to the .asmdef file.