How do I delete empty classes？？？

[luckyxianxian]

Hello, first of all, thank you very much for your code, let me benefit a lot.
Second, I want to know how to modify the code to remove empty classes from the dataset. I post a slight change but always report error:
RuntimeError: cuDNN error: CUDNN_STATUS_NOT_INITIALIZED.
But restore works again, and I suspect this isn't a cuda/cudnn issue, so I'm eager to find out.
Looking forward to your early reply!