meshpy.tet.build's insert_points keyword argument isn't implemented?

I'd like to use TetGen through meshpy. I have a PLC describing my domain's boundary, and I'd like to add some additional points (in the interior of the domain) to the mesh, so that after meshing I'll have a mesh which satisfies a maximum volume constraint on the tetrahedra, and which will additionally include my extra points among the mesh's vertices.

I believe the way to do this is by using the feature described in [section 4.2.8 of TetGen's manual](http://wias-berlin.de/software/tetgen/1.5/doc/manual/manual005.html#cmd-i).

Judging from the documentation for `meshpy.tet.build` from [these docs](https://documen.tician.de/meshpy/tri-tet.html#meshpy.tet.MeshInfo), it appears that `build` takes a keyword argument `insert_points` which is a `MeshInfo` specifying the extra points. I checked the implementation of `build` in the source, and `insert_points` doesn't appear to be used for anything other than setting a flag in `options` at the moment.

I'm also not sure how to use `insert_points`. Something like this?
```py
main_info = ... # set up this MeshInfo already...
insert_info = MeshInfo()
insert_info.set_points([my_special_point])
mesh = build(main_info, ..., insert_points=insert_info)
```