How to subtract 2 hours from time formatted as string

My initial string looks like following:

a1 = "06:00:00"
a2 = "01:00:00"

I want to set the time back by two hours.

How to get the following output (in string format)?

a1_new = "04:00:00"
a2_new = "23:00:00"

>Solution :

Here you go!

from datetime import datetime, timedelta

a1 = "06:00:00"

x = datetime.strptime(a1, "%H:%M:%S") - timedelta(hours=2, minutes=0)

y = x.strftime("%H:%M:%S")

print(y)

Steps:

1. Convert HMS into a DateTime Object
2. Minus 2 hours from this
3. Convert the result into a String that only contains Hour Minute & Second