duration.py

from datetime import datetime


def make_datetime(date, time):
    return datetime(
        year=date.year, 
        month=date.month, 
        day=date.day,
        hour=time.hour,
        minute=time.minute,
        second=time.second
    )


def parse_duration(duration):
    seconds = duration.total_seconds()
    hours = total_seconds // 3600
    
    seconds %= 3600 
    minutes = seconds // 60
    
    seconds %= 60
    
    return hours, minutes, seconds


start = make_datetime(start_date, start_time)
end = make_datetime(end_date, end_time)

duration = end - start

hours, minutes, seconds = parse_duration(duration)

print(f'{hours}h, {minutes}min and {seconds}s')