public function getBindings() {
        $keys = func_num_args() < 1 ? array_keys($this->bindings) : func_get_args();
        $args = [];
        foreach ($keys as $item) {
            if (!array_key_exists($item, $this->bindings)) {
                continue;
            }
            $args = array_merge($args, $this->bindings[$item]);
        }
        return $args;
    }