We have first improved the readability of our code by grouping the related import statements. We next broke out the callback methods into their own class and module, in order to further reduce the complexity of our code.
We had already taken the same OOP approach by having the ToolTip class reside in its own module and by internationalizing all GUI strings in the previous recipes. In this recipe, we went one step further in refactoring by passing our own instance into the callback method's class that our GUI relies upon. This enables us to use all of our GUI widgets.
Now that we better understand the value of a modular approach to software development, we will most likely start with this approach in our future software designs.