time.txt/tx

#!/usr/bin/env python3

from datetime import datetime, timedelta
import argparse

# Parse command line arguments
parser = argparse.ArgumentParser(prog='time.txt', description="Description")
subparsers = parser.add_subparsers(help='sub-command help', dest='mode')
 
parser.add_argument("-f", "--file")

# create the parser for the "a" command
parser_a = subparsers.add_parser('total', help='a help')

# create the parser for the "b" command
parser_b = subparsers.add_parser('add', help='b help')
parser_b.add_argument("time")
parser_b.add_argument("description")

args = parser.parse_args()

filename = args.file if args.file else 'time.txt'

if not args.mode or args.mode == "total":
    with open(filename, 'r') as time_file:
        total_time = timedelta()

        for line in time_file:
            date_time_description = line.split(" ", 2)
            
            hours, minutes = date_time_description[1].split(':', 1)
            delta = timedelta(hours=int(hours), minutes=int(minutes))
            
            total_time += delta

        print('Total time: ', total_time)

elif args.mode == "add":
    with open(filename, 'a') as time_file:
        time_file.write("A new line")