The standard library

Hundreds of ready modules ship with Python. Before writing something yourself, check whether a ready solution exists; it saves time and is more reliable.

sys reports about the interpreter (sys.version, sys.argv). os talks to the operating system. Writing file paths with pathlib is cleaner and works the same everywhere.

import sys, os
from pathlib import Path

print(sys.version_info[:2])
print(os.getcwd())
for p in Path(".").glob("*.py"):
    print(p.name, p.stat().st_size)

datetime handles dates and times, random makes random choices, and logging records what the program does to a file or the screen; unlike print it has levels (DEBUG, INFO, WARNING, ERROR).

import logging, random
from datetime import date, timedelta

logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")
deadline = date.today() + timedelta(days=14)
logging.info("deadline is %s", deadline)
print(random.choice(["red", "green", "blue"]))