How to install wxpython ubuntu 16.04
I could install it by typing in a terminal:
sudo apt-get install python-wxgtk3.0
I don't know but I think that the older versions (2.8, 2.6, …) aren't currently in the 16.04 repositories.
Meanwhile it's possible to install wxPython with sudo pip install wxpython, eventually you have to use sudo pip install --upgrade wxpython. If you need 4.x which isn't provided by Ubuntu (for some years) this is the sanest option.