random output to stdout or stderr

randout.py

import sys
import time
import random

print(f"hello from {sys.argv[0]}")

out = 0
err = 0

while out < 10 and err < 10:
    choice = random.randint(0, 1)
    if choice > 0:
        sys.stdout.write(f'out {out}...\n')
        sys.stdout.flush()
        out += 1
    else:
        sys.stderr.write(f'err {err}...\n')
        sys.stderr.flush()
        err += 1
    time.sleep(1)