Error with label, ch1 prototype

Hello, I have had my code working at one point, but I went back to it today and it fails. Attached is my colab notebook. I’m identifying trees in ky with the lessons from chapter q.

KeyError: Caught KeyError in DataLoader worker process 2.
Original Traceback (most recent call last):
File “/usr/local/lib/python3.7/dist-packages/fastai/data/”, line 246, in encodes
return TensorCategory(self.vocab.o2i[o])
KeyError: 'trees