Invalid daylight saving time for Italy CET in 1976

[Angelo]

In 1976, Italy, the daylight saving time starts at may 30 and ends at september 26. However pytz reports always +1 hour (UTC+1) and not +2 (UTC+1 +1 hour for daylight saving time). This problem affects all dates before 1976-09-27.

# --- sample code
import datetime
import pytz

d1 = datetime.datetime(1976, 9, 26, 0, 0, 0, 0) # Last day in which daylight saving time is in effect
d2 = datetime.datetime(1976, 9, 27, 0, 0, 0, 0) # First dat after daylight saving time

cet = pytz.timezone("CET")

d1z = cet.localize(d1)
d2z = cet.localize(d2)

#-------

results:

d1z is "1976-09-26 00:00:00+01:00" <---- it should have been +02
d2z is "1976-09-27 00:00:00+01:00" <---- ok

Tried Pendulum and it seems having the same problem.

In Javascript (Chrome) it works:

new Date(1976, 8, 26) is "Sun Sep 26 1976 00:00:00 GMT+0200 (Ora legale dell’Europa centrale)"
new Date(1976, 8, 27) is "Mon Sep 27 1976 00:00:00 GMT+0100 (Ora standard dell’Europa centrale)"

references: https://www.timeanddate.com/time/change/italy?year=1976

[Stuart Bishop (stub)]

Use pytz.timezone("Europe/Rome") for Italy's timezone. CET is deprecated (like all non-Region/City zonenames), for the very reason that often individual regions do not follow the same rules as their surrounding regions.

[Angelo (gorgoroth)]

I forgot to mention that I tried "Europe/Rome" with same results.

[Angelo (gorgoroth)]

I reopened this bug report because even changing the timezone to "Europe/Rome" does not solve.