ONNX export error for "RoiAlign"

When I try to export the “roi_align” operator in torchvision to onnx, I meet the following error.

Do you know how to fix it? Thank you!

RuntimeError: ONNX export failed on an operator with unrecognized namespace torchvision::roi_align. If you are trying to export a custom operator, make sure you registered it with the right domain and version. Otherwise, please report a bug.

Based on the error message I guess you might need to register this custom operation as described here.