KeyError: 'epoch' by hrnetv2_w18_imagenet_pretrained.pth

[SmallGGgg]

When I run hrnet18, the following error occurs, how to solve it?
Creating model... => loading pretrained model ../models/hrnetv2_w18_imagenet_pretrained.pth Starting training... Traceback (most recent call last): File "train.py", line 97, in <module> main(opt) File "train.py", line 64, in main model, optimizer, start_epoch = load_model( File "/media/cvlab/F/NGF/FairMOT-master/src/lib/models/model.py", line 40, in load_model print('loaded {}, epoch {}'.format(model_path, checkpoint['epoch'])) KeyError: 'epoch'