This script demonstrate the `flush` argument of print() function.

printflush.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-

from __future__ import print_function
from time import sleep

string = "The words in this sentence should appear letter by letter."

print("Please wait if you don't see another sentence appearing below.", end="\n\n")

for characters in string:
    # If flush disabled the another line will appear at once and not char by char.
    print(characters, end="", flush=True)
    sleep(.1)

No difference with or without flush. Python 3.9 Windows 10 Pro

I agree with this