example6.py

import argparse
import datetime

parser = argparse.ArgumentParser(description='Returns a string containing the name and age of the person')
parser.add_argument('-f', '--first', help='first name', type=str, required=False, dest='first_name')
parser.add_argument('-l', '--last', help='last name', type=str, required=True, dest='last_name')
parser.add_argument('--yob', help='year of birth', type=int, required=False, dest='birth_year')

args = parser.parse_args()

if args.first_name:
    names = [args.first_name]
else:
    names =  []

names.append(args.last_name)
full_name = ' '.join(names)

current_year = datetime.datetime.utcnow().year
age = current_year - args.birth_year

print(f'{full_name} is {age} years old.')