How to re-write this bash script in Python?

[random832 at fastmail.us]

On Thu, Jul 30, 2015, at 14:31, sutanu.das at gmail.com wrote:
> _year=$(date -d "-5 hour" +%Y)
> _month=$(date -d "-5 hour" +%m)
> _day=$(date -d "-5 hour" +%d)
> _hour=$(date -d "-5 hour" +%H)

What is the purpose of the -5 hour offset? Is it an attempt to
compensate for timezones?