Invesalius crashes due to missing import when starting

[David]

Installed Invesalius from the PPA onto a laptop running Ubuntu 18.04.3 (Bionic Beaver 64-bit) with MATE 1.20.1 desktop (a Gnome variant). Installation was smooth.

When I try to run it from a command prompt, I get an error and it exits. It never gets far enough to put anything on the desktop. The error is:

david@Lappy2:~$ invesalius3
Traceback (most recent call last):
  File "app.py", line 44, in <module>
    import wx
  File "/usr/lib/python2.7/dist-packages/wxPython-4.0.1-py2.7-linux-amd64.egg/wx/__init__.py", line 17, in <module>
    from wx.core import *
  File "/usr/lib/python2.7/dist-packages/wxPython-4.0.1-py2.7-linux-amd64.egg/wx/core.py", line 12, in <module>
    from ._core import *
ModuleNotFoundError: No module named 'wx._core'