Sudoku Solver

A sudoku solver written in Python 3 with a gtk 3 GUI.

Usage: There are 2 options.

1. Make the file executable and run from the command line: ./sudoku.py
2. python sudoku.py (Use python 3)

I created this quite a while ago, when I didn’t really pay attention to commenting the code or many other good practices like that one. But it works, it has been able to solve all the sudokus that I’ve tried.

Could it be better coded, better optimized, more readable?
-Probably.. Right now I’m going to struggle to understand my own code. But I plan on revising it to better standards. Hopefully I will get around to doing that soon.