def _process_config(self):
        """Traverses the config and adds master keys and regional clients as needed."""
        self._user_agent_adding_config = botocore.config.Config(user_agent_extra=USER_AGENT_SUFFIX)

        if self.config.region_names:
            self.add_regional_clients_from_list(self.config.region_names)
            self.default_region = self.config.region_names[0]
        else:
            self.default_region = self.config.botocore_session.get_config_variable("region")
            if self.default_region is not None:
                self.add_regional_client(self.default_region)

        if self.config.key_ids:
            self.add_master_keys_from_list(self.config.key_ids)
Traverses the config and adds master keys and regional clients as needed.