ERROR:ZeroDivisionError: division by zero

[RumengYi]

how can i slove this problem when i run python train.py ../config/pascal_unet_res18_scse.yaml?
Traceback (most recent call last):
File "train.py", line 159, in
loss = loss_fn(preds, labels)
File "/home/yirumeng/anaconda3/envs/Pytorch/lib/python3.6/site-packages/torch/nn/modules/module.py", line 547, in call
result = self.forward(*input, **kwargs)
File "/home/yirumeng/code/CAM/pytorch-segmentation-master/src/losses/multi/init.py", line 26, in forward
loss = self.criterion(preds, labels)
File "/home/yirumeng/anaconda3/envs/Pytorch/lib/python3.6/site-packages/torch/nn/modules/module.py", line 547, in call
result = self.forward(*input, **kwargs)
File "/home/yirumeng/code/CAM/pytorch-segmentation-master/src/losses/multi/lovasz_loss.py", line 77, in forward
total_loss += lovasz_softmax_flat(prb, lbl, self.ignore_index, self.only_present)
File "/home/yirumeng/code/CAM/pytorch-segmentation-master/src/losses/multi/lovasz_loss.py", line 56, in lovasz_softmax_flat
return total_loss / cnt
ZeroDivisionError: division by zero

[carlodizon03]

try:
    z = total_loss / cnt
except ZeroDivisionError:
    z = 0
return z