setup new_label_tensor when there is not label files

[ricoms]

When trying to replicate your code I had to do some fixes, this test mode was one of them. When running on test mode it does not create the new_label_tensor variable... but then this variable is required in the function root logic. I suppose you mostly used the npy logic in there? But that might have worked only if there was empty label files for test, or you used a different test dataset... full of assumptions here.

Hope this fix helps you