byby

   ME:
   def (x: int):
      for i in range(x):
         print(i)

   #unit testable code (without using dependency injection tricks)

   def cool_function(x: int) -> None:
       IO_function(logic_function(x))

   def logic_function(x: int) -> List[int]:  
       return [i for i in range(x)]

   def IO_function(x: Any) -> None:
       print(x)
       
   def test_output():
       assert logic_function(4) == [i for i in range(4)]

   (Btw making print formatting unit testable means segregating the formatting from the print. Produce the string first, test that, then print, because print can never be unit tested by definition)