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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def items(self, region_codes, include_subregions=False):
 """ Returns calendar classes for regions :param region_codes list of ISO codes for selected regions :param include_subregions boolean if subregions of selected regions should be included in result :rtype dict :return dict where keys are ISO codes strings and values are calendar classes """

        items = OrderedDict()
        for code in region_codes:
            try:
                items[code] = self.region_registry[code]
            except KeyError:
                continue
            if include_subregions:
                items.update(self.get_subregions(code))
        return items