Sum up Time difference

[Gribouillis]

I do not see how I can get from this:

You can also keep track of a cumulated time difference,

cum_time_dif = datetime.timedelta() # initialize cumulated time difference to a null duration
...
t_end = datetime.strptime(end_t, "%m/%d/%Y %I:%M:%S %p")                    
t_start = datetime.strptime(start_t, "%m/%d/%Y %I:%M:%S %p")
time_dif = t_end - t_start
print(f" Time Difference = {time_dif}-{type(time_dif)}")
cum_time_dif += time_dif # increase cumulated time difference
...
print(f'Cumulated Time Difference = {cum_time_dif}')