A concrete datetime.tzinfo subclass that represents an IANA time zone specified by the string key. Calls to the primary constructor will always return objects that compare identically; put another way, barring cache invalidation via ZoneInfo.clear_cache(), for all values of key, the following assertion will always be true:
This is a read-only attribute that returns the value of key passed to the constructor, which should be a lookup key in the IANA time zone database (e.g.