This wasn't the point. Also map is not recommended for usage in python. Stylistically the convention says you should be using a list comprehension in place of f

This wasn't the point. Also map is not recommended for usage in python. Stylistically the convention says you should be using a list comprehension in place of filter and map. Also did you do your tests with regular expressions? I specifically mentioned I didn't use regexps but it would be dramatically faster if you used it instead of the replace method. I'll reiterate the point. The point is there is a pattern you can follow where you can move from one "type space" into another "type space" then back because the other type space may be easier to write transformations. Obviously from the this thread, the serialized type space may not be the best way for python. But there are many other contexts where this it is better and my point is, category theory allowed me to derive this general pattern. That's it.