public function delete_lock_instance($name) {
        if (!array_key_exists($name, $this->configlocks)) {
            throw new cache_exception('The requested store does not exist.');
        }
        if ($this->configlocks[$name]['default']) {
            throw new cache_exception('You can not delete the default lock.');
        }
        foreach ($this->configstores as $store) {
            if (isset($store['lock']) && $store['lock'] === $name) {
                throw new cache_exception('You cannot delete a cache lock that is being used by a store.');
            }
        }
        unset($this->configlocks[$name]);
        $this->config_save();
        return true;
    }