argparse argument dependency

Question

If I call the script below with these options:

--user u1 --password p1 --foo f1   --user u2   --user u3 --password p3

Then it will print:

Answer 1

Define a custom user type which holds both username and password.

def user(s):
    try:
        username, password = s.split()
    except:
        raise argparse.ArgumentTypeError('user must be (username, password)')

group.add_argument('--user', type=user, action='append')