public function post($data, $value = null)
    {
        if (is_array($data)) {
            foreach ($data as $key => $val) {
                $this->post[$key] = $val;
            }
        } else {
            if ($value === null) {
                $this->post = $data;
            } else {
                $this->post[$data] = $value;
            }
        }
        return $this;
    }