How can I take use of the param.npz files?

[EternalEvan]

Thanks for your remarkable works.
I have run the demo.py on my own dataset and get the output parameters file XXX_params.npz.My question is how can I get the rendered hd_image from the .npz files.In other words,can I use the params like 'body_pose' and 'hand_pose' to get a rendered image?I wonder if you have some APIs to solve my problem.
Thanks!