Solved by Shisho_Sama in post #2 
              
              
                Setting num_workers=0 actually showed the real problem which simply was : 
AttributeError: 'SVHN_Dataset' object has no attribute 'is_train_split' 
I simply had a misspelling and that was causing the issue. basically as noted here and here : 

this error only occurs when you try to do multiprocessin…