Once again, we simply need to import the LineNumbers class at the top of our texteditor.py file:

from linenumbers import LineNumbers

With that taken care of, we just need to instantiate the class in our __init__ method. Since the code is already set up to apply our custom scrolling to an attribute named lne_numbers, let's delete all references to that attribute in __init__, except for the call to pack at the end, and replace them with this one line:

self.line_numbers = LineNumbers(self, self.text_area, bg="grey", fg="white", width=1)

This ensures that our custom scrolling and event bindings will still apply to this newly created class.

Give the editor another whirl and check out the new dynamic line numbers.

There remains one more thing to take care of in this chapter, while the idea of indexing and tagging is fresh in our memories—the find/replace window.

At the end of the last chapter, we left this just as a pop-up box with no real functionality. It's time to bring it to life!