Errors with inferencing using multiple GPUs

[Lucas-SJY]

Hi, I encountered a problem with multiple GPU inference.
I was using the following command to run
python inference_realesrgan.py -n RealESRGAN_x4plus -i ${back_dir}/${frames_wav2lip}/${filename} --output ${back_dir}/${frames_hd}/${filename} --outscale 3.5 --face_enhance -g 0 1 2 3
or
python inference_realesrgan.py -n RealESRGAN_x4plus -i ${back_dir}/${frames_wav2lip}/${filename} --output ${back_dir}/${frames_hd}/${filename} --outscale 3.5 --face_enhance -g 0,1,2,3
However, I always get the error saying
usage: inference_realesrgan.py [-h] [-i INPUT] [-n MODEL_NAME] [-o OUTPUT] [-dn DENOISE_STRENGTH] [-s OUTSCALE] [--model_path MODEL_PATH] [--suffix SUFFIX] [-t TILE] [--tile_pad TILE_PAD] [--pre_pad PRE_PAD] [--face_enhance] [--fp32] [--alpha_upsampler ALPHA_UPSAMPLER] [--ext EXT] [-g GPU_ID] inference_realesrgan.py: error: argument -g/--gpu-id: invalid int value: '0,1,2,3'

Can anyone inference with multiple GPUs? Can any give me some sample of how to use the --gpu-id parameter?