Multi-gpu usage

model = insightface.app.FaceAnalysis()
ctx_id = 0
model.prepare(ctx_id = ctx_id, nms=0.4)

This is how i build model. with ctx_id param i can select only one gpu for model,

how can i choose all 4 gpus for model, is there any way ? putting in list [0,1,2,3] does not work btw.

Thanks!