tvtk polydata does not tab-complete "points"

I'm using tvtk for the first time, and I find it a bit difficult to know what attributes to use with the various tvtk objects. Using tab-complete in an iPython shell is helpful (although still challenging with so many attributes available and most being not useful). And then I found a case where the attribute I want exists but does not tab-complete! Specifically, I used `tvtk.XMLPolyDataReader` to read in a .vtp file and get the output:
```
treader = tvtk.XMLPolyDataReader(file_name=filename)
treader.update()
data = treader.get_output()
```
I want the points. After browsing the docs, I found that I can get them with `data.points`. However, `data.points` does not tab-complete. If so, I would have found it a lot earlier. I'm also concerned there are other attributes I could use that I am missing.

My system is MacOS 10.12.6 with software components installed via Macports:
```
py36-mayavi @4.6.2_0 (active)
python36 @3.6.7_0 (active)
vtk @8.1.1_1+python36 (active)
```