Have you ever wished you could add a method to an existing class that you don’t have the code for?
Well, now you can, with categories.
Categories let you extend an existing class with whatever method you deem fit. It is pretty useful to add helper methods to other classes that help parse the date in a way the class make perhaps did not intend. You can also use it to split up your own classes so that if you have some big omni-class that does several things, you can opt in to just the parts you want by only including those categories.