比较两个时区感知日期时间

Question

Most probably, this question is asked hundred times, but I couldn't still find the answer. I have the following code:

import pytz
import datetime
from pytz import timezone

tz_moscow = timezone('Europe/Moscow')
tz_yerevan = timezone('Asia/Yerevan')

dt1 = tz_yerevan.localize(datetime.datetime(2011, 7, 20, 0, 0, 0, 0))
dt2 = tz_moscow.localize(datetime.datetime(2011, 6, 20, 0, 0, 0, 0))
print (dt2.utcoffset()) # Expected 3, actual result - 4
print (dt1)
print (dt2)
print (dt1 == dt2)

I have two questions:

1. Timezone offset for Moscow is GMT+3, but for some reason, I see "4" for some reason
2. Can I compare two timezone aware datetimes by just doing dt1 < dt2

Answer 1

As you can see in these tests timezone aware datetime can be compared. They will be compared with their timezone offset.

import datetime
from pytz import timezone

tz_moscow = timezone('Europe/Moscow')
tz_yerevan = timezone('Asia/Yerevan')

standard_datetime_object = datetime.datetime(2022, 1, 18, 0, 0, 0, 0)

moscow_datetime_object = tz_moscow.localize(standard_datetime_object) 
yerevan_datetime_object = tz_yerevan.localize(standard_datetime_object)
yerevan_datetime_object_1h = tz_yerevan.localize(datetime.datetime(2022, 1, 18, 1, 0, 0, 0))

print(f"datetime object without UTC offset:\n{standard_datetime_object}\n")
print(f"datetime object with UTC offset +3:\n{moscow_datetime_object}\n")
print(f"datetime object with UTC offset +4:\n{yerevan_datetime_object}\n")

print(f"is same time with +3 greater than one with +4:\n{moscow_datetime_object > yerevan_datetime_object}\n")
print(f"is same time with +3 less than one with +4:\n{moscow_datetime_object < yerevan_datetime_object}\n")

print(f"is one o'clock in yerevan equal to midnight in moscow:\n{yerevan_datetime_object_1h == moscow_datetime_object}")

And the timezone offset is different during winter and summer so in july it is +4 wheras now (in january) it is +3. (same goes for yerevan)