* better comment the code (why, how) * better split or merge functions * use `os.path.join()` for file path * use `entry.state(['disabled'])` instead of `state='disabled'` (deprecated). * https://codereview.stackexchange.com/questions/239821/simple-gui-unit-converter-with-tkinter. Separate widget creation and widget positioning * Do not create variable for labels except if label should be updated by a StringVar * Initialize StringVar with the actual value `(value='blabla').` Avoid using `set` * String concatenation must be done with `''.join(list_of_strings)`