when I run this code for classification without token-label, it has an error

[MaltoseFlower]

details for this error
Traceback (most recent call last):
File "main.py", line 964, in
main()
File "main.py", line 678, in main
optimizers=optimizers)
File "main.py", line 798, in train_one_epoch
loss = loss_fn(output, target)
File "/mnt/cephfs/home/x/anaconda3/envs/unet/lib/python3.7/site-packages/torch/nn/modules/module.py", line 889, in _call_impl
result = self.forward(*input, **kwargs)
File "/mnt/cephfs/home/x/anaconda3/envs/unet/lib/python3.7/site-packages/timm/loss/cross_entropy.py", line 35, in forward
loss = torch.sum(-target * F.log_softmax(x, dim=-1), dim=-1)
File "/mnt/cephfs/home/x/anaconda3/envs/unet/lib/python3.7/site-packages/apex/amp/wrap.py", line 28, in wrapper
return orig_fn(*new_args, **kwargs)
File "/mnt/cephfs/home/x/anaconda3/envs/unet/lib/python3.7/site-packages/torch/nn/functional.py", line 1672, in log_softmax
ret = input.log_softmax(dim)
AttributeError: 'tuple' object has no attribute 'log_softmax'

can u help me ? thanks.