example for mask + points multi-metric registration?

[dyf]

We have been building a 3D anatomical template for one of our lightsheet systems. We find 3D mask-based alignment does a great job but would like to refine the transform with a set of manually placed XYZ fiducials.

We have been attempting this with ANTsPy, but have been struggling with understanding the correct way to do this from the documentation. Could someone provide an example?

cc @yonibrowning, @sharmishtaa