Error on running trainer.py

[sabuj7177]

I followed all the commands provided in Getting_Started.md file. Previously i installed all the dependent modules mentioned in install.md file. When i run the trainer.py with necessary arguments, the following error occurs.

Distributed training OFF
Loading model from ../models/CovidAID_transfered.pth.tar
Freezing feature layers
100%|██████████| 115/115.0 [02:07<00:00, 1.11s/it]
0%| | 0/10.0 [00:00<?, ?it/s]
Traceback (most recent call last):
File "/home/sabuj/PycharmProjects/CovidAid/tools/trainer.py", line 438, in
start_epoch=args.start, save_path=args.save, freeze_feature_layers=args.freeze)
File "/home/sabuj/PycharmProjects/CovidAid/tools/trainer.py", line 147, in train
for i, (inputs, target) in tqdm(enumerate(val_loader), total=len(val_dataset)/BATCH_SIZE):
File "/home/sabuj/PycharmProjects/CovidAid/venv/lib/python3.6/site-packages/tqdm/std.py", line 1178, in iter
for obj in iterable:
File "/home/sabuj/PycharmProjects/CovidAid/venv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 210, in next
return self._process_next_batch(batch)
File "/home/sabuj/PycharmProjects/CovidAid/venv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 230, in _process_next_batch
raise batch.exc_type(batch.exc_msg)
IndexError: Traceback (most recent call last):
File "/home/sabuj/PycharmProjects/CovidAid/venv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 42, in _worker_loop
samples = collate_fn([dataset[i] for i in batch_indices])
File "/home/sabuj/PycharmProjects/CovidAid/venv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 42, in
samples = collate_fn([dataset[i] for i in batch_indices])
File "/home/sabuj/PycharmProjects/CovidAid/tools/read_data.py", line 157, in getitem
image_name = random.choice(self.image_names[class_idx])
File "/usr/lib/python3.6/random.py", line 260, in choice
raise IndexError('Cannot choose from an empty sequence') from None
IndexError: Cannot choose from an empty sequence

Can anyone please suggest what might be causing this issue?