AttributeError: module'itk' has no attribute'GradientDifferenceImageToImageMetric'

When I use itk’s GradientDifferenceImageToImageMetric in a python environment, the above error occurred.
Then I did not find the file in the packages directory.
Why does this happen, the itk version is 5.1.2 and the python version is 3.8.
Thank you!

GradientDifferenceImageToImageMetric is currently not wrapped. Adding the wrapping specification should not be hard. It should be similar to other wrap specifications for metrics, e.g. MeanSquaresImageToImageMetric. Do you mind submitting a patch?

Thanks for your reply, I will try to solve it.