Call nested function from another function in python?

Question

I have a function inside inside another and a third function. How can I call my nested function inside of my third function? Is there any special libraries I can use? I am not allowed to edit a() or b(), only c().

def a():
    def b():
        print("hi")

def c():
    # code only here to call b() to print

Answer 1

When you do this, function b is defined locally within a. This means that it cannot be accessed by default outside of a. There are two main ways to solve this, but both involve modifying a:

1. The global keyword (not recommended)

   def a():
       global b
       def b():
           print("hi")
   

   Here the global keyword sets b up as a global variable, so that you can then access it by calling it normally from within c. This is generally frowned upon.

2. Returning the function from a and passing it to c

   def a():
       def b():
           print("hi")
       return b
   
   def c(b):
       #your code
   

   Then, when you call c, you should pass b to it, which a will have returned. You can either do so thus:

   b = a()
   c(b)
   

   Or you can simply call a every time you call c, thus:

   c(a())
   

   If you choose to do this, you can then define c thus:

   def c():
       b = a()
       #your code here
   

   which would allow you to simply call c normally, thus:

   `c()`
   

Answer 2

This is not possible due to the way that Python scope works. b() is local to a(), and so does not exist within c().

EDIT: commenter is correct, the suggestion I initially gave doesn't work -- so this definitely just isn't possible.