: They told me about this experiment. I'll learn who you are only from the first comment you leave. Hello unknown. Bob : Hi Bob. I don't think we know each other. I'm in the New Zealand office, Auckland to be precise. Alice : That's quite a timezone difference. I'm on the other side of the Earth, I just checked. Bob : Bom dia in Lisbon! Correct? Time passes and we haven't written a single line of code. I start Alice def main(): pass : Let's make it a console app Bob import argparse def main(): parser = argparse.ArgumentParser(description="TBD") args = parser.parse_args() : TBD? Come on. Alice - parser = argparse.ArgumentParser(description="TBD") + parser = argparse.ArgumentParser(description="Think of a number. I'll find it out") : I'm not sure Bob args = parser.parse_args() + print(guess_number(args)) def guess_number(args): return 42 : I just checked Presumably not the reason you chose this number. How about this? Alice https://xkcd.com/42/ import os def main(): parser = argparse.ArgumentParser(description="Think of a number and I'll find it out") parser.add_argument("number", nargs="?", type=int, help="Your number if I didn't find it out") args = parser.parse_args() guess_number(args.number) def guess_number(number): if number is None: print(42) else: clear_screen() print("Just what I said: {}".format(number)) def clear_screen(): if os.name == "nt": os.system("cls") else: os.system("clear") : How about the usual boilerplate? Bob import argparse ... if __name__ == "__main__": main() : Mission completed. We’ve written a program together communicating only in code. Alice