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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 do_api_calls_update_cache(self):
        ''' Do API calls to each region, and save data in cache files '''

        if self.route53_enabled:
            self.get_route53_records()

        for region in self.regions:
            self.get_instances_by_region(region)
            if self.rds_enabled:
                self.get_rds_instances_by_region(region)
            if self.elasticache_enabled:
                self.get_elasticache_clusters_by_region(region)
                self.get_elasticache_replication_groups_by_region(region)

        self.write_to_cache(self.inventory, self.cache_path_cache)
        self.write_to_cache(self.index, self.cache_path_index)