How to load CUB-200-2011 in pytorch?

I am trying to do fine-grained image classification for CUB-200-2011 dataset, couldn’t figure out the correct way for loading the data. I’m using pre-trained ImageNet ResNet-101 for training by freezing all layers except last two layers. Suggest a way to for data loading in Pytorch.

It seems that this repository has implemented a custom Dataset for CUB-200-2011.

That shows following problem,
How do I resolve my error?