sum_range.py

import re
import os


FOLDER = 'files'


def get_paths():
    return [os.path.join(FOLDER, f) for f in os.listdir(FOLDER)]


def extract_datetime(filepath):
    regex = r'(?P<date>\d{4}-\d{2}-\d{2})--(?P<time>\d{2}:\d{2})'
    match = re.search(regex, filepath)
    return [match.group('date'), match.group('time')]


def sum_hours(hours):
    total_secs = 0
    for tm in hours:
        time_parts = [int(s) for s in tm.split(':')]
        total_secs += (time_parts[0] * 60 + time_parts[1]) * 60

    total_secs, _ = divmod(total_secs, 60)
    hr, min = divmod(total_secs, 60)
    return "%d:%02d" % (hr, min)


def sum_total_of_times_in_range(start_date, end_date):
    # Start and end date in ISO format YYYY-MM-DD
    paths = get_paths()
    times = []
    start_date_to_number = int(start_date.replace('-', ''))
    end_date_to_number = int(end_date.replace('-', ''))
    date_range = range(start_date_to_number, end_date_to_number + 1)
    for path in paths:
        date = extract_datetime(path)[0]
        date_number = int(date.replace('-', ''))
        if date_number in date_range:
            time = extract_datetime(path)[1]
            times.append(time)

    return sum_hours(times)


start_date = input('Enter start date (YYY-MM-DD): ')
end_date = input('Enter end date (YYY-MM-DD): ')

print(sum_total_of_times_in_range(start_date, end_date))