Key Error in training pix2pix with unaligned data

[Ashish-Abraham]

I have been trying to train a pix2pix model on ukiyoe2photo dataset as given in this notebook by SnapML. The create_eval_dataloader function is giving a key error with the following log.

Traceback (most recent call last):
File "train.py", line 14, in
trainer.start()
File "/content/CAT/trainer.py", line 328, in start
(epoch, total_iter))
File "/content/CAT/trainer.py", line 272, in evaluate
metrics = self.model.evaluate_model(iter)
File "/content/CAT/models/pix2pix_model.py", line 507, in evaluate_model
self.set_input(data_i)
File "/content/CAT/models/pix2pix_model.py", line 439, in set_input
self.real_A = input['A' if AtoB else 'B'].to(self.device)
KeyError: 'B'

Seems like the data produced by the eval_dataloader contains only 2 keys: 'A' and 'A_paths'. Apparently it has no 'B' and 'B_paths' field.
It would be great if you may help me with it.