The Realm.DoesNotExist exception will never be raised if we pass a
string_id as in that case zerver.models.get_realm function would be
used for fetching. realm.zerver.models.get_realm uses filter query
so the exception will not be raised even if there are no realm which
matches the query.
Tests added by tabbott.
This new library is intended to make it easy for management commands
to access a realm or a user in a realm without having to duplicate any
of the annoying parsing/extraction code.
Vishnu Ks
Tim Abbott