KeyError: 'Non-existent config key: MODEL.OneNet'

# Convert model to onnx failed
conmand:    
```
python3 caffe2_converter.py  --format onnx --config-file $dir/onenet.res18.nodcn.yaml --output onnx MODEL.WEIGHTS model_0014999.pth
```
report: 
```
KeyError: 'Non-existent config key: MODEL.OneNet'
```
env:   
```
pytorch: 1.6.0
torchvision: 0.7.0
onnx: 1.7.0 
```
# How to convert model to onnx