yolact: KeyError while running the model on Custom Dataset

Hi! Thanks for this repo. I am trying to run this model on a custom dataset and I face this error. Here is the stack trace:

Traceback (most recent call last):
  File "train.py", line 386, in <module>
    train()
  File "train.py", line 215, in train
    for datum in data_loader:
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 582, in __next__
    return self._process_next_batch(batch)
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/dataloader.py", line 606, in _process_next_batch
    raise Exception("KeyError:" + batch.exc_msg)
Exception: KeyError:Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/worker.py", line 99, in _worker_loop
    samples = collate_fn([dataset[i] for i in batch_indices])
  File "/usr/local/lib/python3.6/dist-packages/torch/utils/data/_utils/worker.py", line 99, in <listcomp>
    samples = collate_fn([dataset[i] for i in batch_indices])
  File "/home/user/yolact/data/coco.py", line 87, in __getitem__
    im, gt, masks, h, w, num_crowds = self.pull_item(index)
  File "/home/user/yolact/data/coco.py", line 126, in pull_item
    file_name = self.coco.loadImgs(img_id)[0]['file_name']
  File "/usr/local/lib/python3.6/dist-packages/pycocotools/coco.py", line 229, in loadImgs
    return [self.imgs[id] for id in ids]
  File "/usr/local/lib/python3.6/dist-packages/pycocotools/coco.py", line 229, in <listcomp>
    return [self.imgs[id] for id in ids]
KeyError: 7

The value changes every time. I have shown an example where the KeyError threw was 7. I followed the answer from issue #40 , but still, the error persists. My class id’s start from 1 and end in 10 (inclusive). Here is my config.py:

my_dataset= dataset_base.copy({
    'name': 'my dataset',
    'train_images': '/home/user/dataset/train/',
    'train_info': '/home/user/dataset/train/via_region_data.json',

    'valid_images':'/home/user/dataset/val/',
    'valid_info': '/home/user/dataset/val/via_region_data.json',

    'has_gt': True,
    'class_names': ('BWK12', 'LWK1', 'LWK2', 'LWK3', 'LWK4', 'LWK5', 'SWK1/2', 'Cage', 'Schraube', 'Stab'),
    'label_map': {1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8, 9:9, 10:10}
})

Here is the configuration:

yolact_base_config = coco_base_config.copy({
    'name': 'yolact_base',

    # Dataset stuff
    'dataset': my_dataset,
    'num_classes': len(spine_dataset.class_names)+1,
    .........
)}