export_for_isaac.py problem, not a valid (.json) file

[AK51]

Hi,

I want to use the export utility,
https://github.com/NVIDIA-AI-IOT/trt_pose/blob/master/trt_pose/utils/export_for_isaac.py

And I saw the example in readme
example: ./export_for_isaac.py --input_checkpoint resnet18_baseline_att_224x224_A_epoch_249.pth

I have put the pth file in the same location and I typed
sudo python3 export_for_isaac.py --input_checkpoint resnet18_baseline_att_224x224_A_epoch_249.pth
But there is an error of
Input topology human_pose.json is not a valid (,json) file...
I have also tried the densenet, same problem....

Does anyone have the same problem? Or did I do anything wrong? Thx