TypeError: unhashable type: 'slice'

[neverstoplearn]

Traceback (most recent call last):
File "/home/zhengxin/anaconda3/envs/pytorch/lib/python3.8/site-packages/torch/multiprocessing/spawn.py", line 59, in _wrap
fn(i, *args)
File "/home/zhengxin/humanpose.pytorch/tools/train.py", line 223, in main_worker
perf_indicator = validate(
File "/home/zhengxin/humanpose.pytorch/tools/../lib/core/function.py", line 204, in validate
name_values, perf_indicator = val_dataset.evaluate(
File "/home/zhengxin/humanpose.pytorch/tools/../lib/dataset/mpii.py", line 100, in evaluate
preds = preds[:, :, 0:2] + 1.0
TypeError: unhashable type: 'slice'

how can i fix it? thanks.