How to fix Python ‘ImportError: No module named wx’ on Ubuntu

Problem:

You want to run a Python script, e.g. Pronterface, but you see an error message like this:

wxPython is not installed. This program requires wxPython to run.
Traceback (most recent call last):
  File "./pronterface.py", line 23, in <module>
    import wx  # NOQA
ImportError: No module named wx

Solution:

sudo apt install python-wxtools