Unable to load 4bit_rdn_x4.pt 

Hello,

I am trying to test pretrained rdn model. I was able to run edsr model but unable to load 4bit_rdn_x4.pt model and facing the below issue while loading. 

Please help.
![image](https://user-images.githubusercontent.com/15530162/108629721-55927280-7487-11eb-9809-ad47e10eb42b.png)
