In my scenario, I want to subtract two dates but when I fetch the date it gives me UTC time and date.  

#first import this library
from pytz import timezone
#convert the date string into object 
now_utc_date=datetime.strptime(now_utc,"%Y-%m-%d %H:%M:%S")
print('utc date and time', now_utc_date)
# now i am changing timezone
now_dubai = now_utc_date.astimezone(timezone('Asia/Dubai'))
print('converted time',now_pacific.strftime("%Y-%m-%d %H:%M:%S")) I hope this code resolve the error

It has been discussed in the community for a while:
https://www.odoo.com/forum/help-1/question/time-zone-problem-in-odoo-118905
https://www.odoo.com/forum/help-1/question/user-timezone-not-applied-to-report-filters-9478
In my opinion there is a logic behind the default treatment of timezones in Odoo:
1) Transactions are recorded with UTC timestamp for all users (server time is UTC)
2) Transactions are displayed to users in their timezone (UTC +TZ delta)

Impacts:
1) For two users working in various timezones to have identical reports requires setting their time to UTC
2) Some transactions recorded same day (late hours) in Western timezones will be timestamped next day on server and will be shown in the reports for next day
3) Some transactions recorded same day (early hours) in Eastern timezones will be timestamped previous day on server and will be shown in the reports for previous day
4) Reports which do not take time as a parameter (only day) will be shown identical to all users. Some transactions from Western timezones day ends (local time) and Eastern timezones day starts (local time) won’t be shown.

Conclusion:
Accountants should be aware of this behavior and should setup their policies respectively:
1) For the reports taking DAY AND TIME as parameters they should login under a UTC-USER
2) For the reports taking only DAY as a parameter they may login either under a LOCAL TIMEZONE USER or under a UTC-USER