[Unity 5.2] The imported type `UnityEngine.Advertisements.ShowResult' is defined multiple times

Hello,

Today I have upgraded my project to Unity 5.2.

I have issues with UnityAds as it gives me errors:

error CS0433: The imported type `UnityEngine.Advertisements.Advertisement' is defined multiple times
error CS0433: The imported type `UnityEngine.Advertisements.ShowResult' is defined multiple times
error CS0433: The imported type `UnityEngine.Advertisements.ShowOptions' is defined multiple times

Any ideas how to fix it?

Thanks in advance!