Build generator of delays to wait between each call

        :param string config_name: configuration name

def ha_get_delay_policy(self, config_name):
        """Build generator of delays to wait between each call

        :param string config_name: configuration name
        """
        config = self.ha_get_config(config_name)
        delay_policy_conf = config.delay_config
        delay_policy_conf = copy.deepcopy(delay_policy_conf)
        delay_policy_conf.update(delay=config.delay)
        return self._retry_delays_class.get(
            config.delay_policy,
            **delay_policy_conf
        )