Is it right to use 'bg_idx = (masks.shape[1] - 1)' ?

[liushenme]

Hi, Your work is very interesting and I have a question about your code. Refer to line 42 in avss/loss.py, bg_idx = (pred_masks.shape[1] - 1) you define background idx as 'masks.shape[1] - 1', which is 70. But after I ran the code, I think the background idx should be 0, which is also defined in label2idx.json. Is there any problem? Thank you in advance.