请问显示keyerror是什么问题

[TGU1912]

按照您的步骤操作，运行完python train.py --config=yolact_hrnet18_config 之后显示这个，您知道是什么问题吗

Traceback (most recent call last):
File "train.py", line 504, in
train()
File "train.py", line 270, in train
for datum in data_loader:
File "/home/zy/anaconda3/envs/mmcv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 345, in next
data = self._next_data()
File "/home/zy/anaconda3/envs/mmcv/lib/python3.6/site-packages/torch/utils/data/dataloader.py", line 385, in _next_data
data = self._dataset_fetcher.fetch(index) # may raise StopIteration
File "/home/zy/anaconda3/envs/mmcv/lib/python3.6/site-packages/torch/utils/data/_utils/fetch.py", line 44, in fetch
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/home/zy/anaconda3/envs/mmcv/lib/python3.6/site-packages/torch/utils/data/_utils/fetch.py", line 44, in
data = [self.dataset[idx] for idx in possibly_batched_index]
File "/home/zy/hrnet/data/coco.py", line 94, in getitem
im, gt, masks, h, w, num_crowds = self.pull_item(index)
File "/home/zy/hrnet/data/coco.py", line 153, in pull_item
target = self.target_transform(target, width, height)
File "/home/zy/hrnet/data/coco.py", line 42, in call
label_idx = self.label_map[label_idx] - 1
KeyError: 9