def get_calendar_class(self, iso_code):
code_elements, is_subregion = self._code_elements(iso_code)<EOL>if is_subregion and iso_code not in self.region_registry:<EOL><INDENT>code = code_elements[<NUM_LIT:0>]<EOL><DEDENT>else:<EOL><INDENT>code = iso_code<EOL><DEDENT>return self.region_registry.get(code)<EOL>
Retrieves calendar class associated with given ``iso_code``.

If calendar of subdivision is not registered
(for subdivision like ISO codes, e.g. GB-ENG)
returns calendar of containing region
(e.g. United Kingdom for ISO code GB) if it's available.

:rtype: Calendar