Functional programming is just imperative programming with heavy heavy restrictions. So yes this can be done, as long as you fully understand what functional programming really is...

A functional program is simply a program that is made up of a single mathematical expression. Complexity is achieved in functional programming by composing smaller expressions into a single big expression. It should be possible to write your entire functional program as a single expression or statement (not saying you should do it, but it should be possible). That's it. That means all your python functions should be a single expression only (use lambda always instead of def; or if you must use def make sure all your variables remain immuted)

If you want to apply like category theory to it, then just make sure your python functions always stick to specific types. Don't let a function take in either a string or an int and return a list or a iterator or any bullshit like that. Keep the typing consistent... If you define all your functions to behave mathematically like only taking in a string and only returning an int, not an int or a None... then you are following category theory.

So nothing like this:

  def someFunc(value):
     if value == "hello"
        return 1
     elif value == 123:
        return [1,"world"]

or this:

  blah = lambda a: "hello" if a is None else 304

If you wanted automated type checking at run time you can use a decorator to check the types of variables going into the function and coming out.

If you try this style at work, people will complain haha, I don't recommend it