public function getPrevPageParams()
    {
        $limit = $this->limit <= 0 ? $this->count : $this->limit;
        $prev_url = $this->offset_key
            . $this->offset
            . $this->limit_key
            . $limit;

        if ($this->count >= $limit) {
            $prev_url = $this->offset_key
                . ($this->offset - $limit)
                . $this->limit_key
                . $limit;
        }
        if ($this->count <= ($this->offset - $limit)) {
            $prev_url = $this->offset_key
                . $this->offset
                . $this->limit_key
                . $limit;
        }
        return $prev_url;
    }