Python 3 Tic Tac Toe with tkinter

This is a tkinter version of my Tic Tac Toe game. This version uses canvas which is better looking and easier to work with. It represents my beginner to intermediate Python 3 skills. Thanks to wonderful community of Stack Overflow and great and detailed tkinter documentation, I have managed to learn more about the tkinter itself, as well as produce a well written code. Since I work alone, there is no one to review my code, so if that's your expertise, please review this code, I would be grateful to learn more about how to improve this and every next code. If your find problems with this program, please send me your feedback, it would be great to improve this code even more. I haven't messed around with try/catch statements because I've tested each step during the writing of this code, but I believe I will manage to insert these as soon as possible.

IMPORTANT!

If you plan to edit this code, please keep in mind that changing some variables can alter the gameplay and can raise errors. Change variables at your own risk. Only the variables for declaring colors are completely safe to edit, as long as you know what you're doing. Also keep in mind that if you change the canvas dimensions, other coordinates need to be changed accordingly. I will try to edit the code to make this process possible without manually altering large amount of code, but for now this is what you get.

I appreciate your feedback on this code. Thanks!