Undefined name: 'root' in resnet.py about gluoncv-torch

[lyuwenyu]

I meet similar error when loading resnet18(pretrained=True). (however other resnet models are ok)

• pyhton 3.6
• pytorch 4.1

NameError                                 Traceback (most recent call last)
<ipython-input-9-f60041f7bcbc> in <module>()
----> 1 m = gcv.models.resnet18(pretrained=True)

~/anaconda3/lib/python3.6/site-packages/gluoncvth/models/resnet.py in resnet18(pretrained, **kwargs)
    223     if pretrained:
    224         model.load_state_dict(torch.load(
--> 225             get_model_file('resnet18', root=root)), strict=False)
    226     return model
    227 

NameError: name 'root' is not defined