dataset cannot return multiple values

[Yukui-1999]

Error occurs when I try to return multiple values of different shapes inside getitem of ffrecord.torch.Dataset
Original Traceback (most recent call last):
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/worker.py", line 308, in _worker_loop
data = fetcher.fetch(index)
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/ffrecord-1.4.0+3f6380c-py3.9-linux-x86_64.egg/ffrecord/torch/dataloader.py", line 156, in fetch
return self.collate_fn(data)
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/collate.py", line 265, in default_collate
return collate(batch, collate_fn_map=default_collate_fn_map)
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/collate.py", line 145, in collate
return elem_type([collate(samples, collate_fn_map=collate_fn_map) for samples in transposed])
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/collate.py", line 145, in
return elem_type([collate(samples, collate_fn_map=collate_fn_map) for samples in transposed])
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/collate.py", line 119, in collate
return collate_fn_map[elem_type](batch, collate_fn_map=collate_fn_map)
File "/data/anaconda3/envs/pl/lib/python3.9/site-packages/torch/utils/data/_utils/collate.py", line 162, in collate_tensor_fn
return torch.stack(batch, 0, out=out)
RuntimeError: stack expects each tensor to be equal size, but got [12, 5000] at entry 0 and [50, 256, 256] at entry 1

Does your tool only support returning one piece of data?