public function startConversation($id, $message)
    {
        if ($this->isEmptyId($id)) {
            throw new InvalidArgumentException;
        }

        if (!$message) {
            throw new InvalidArgumentException;
        }

        $params = [
            'body' => $message
        ];

        $res = $this->call('users/' . $id . '/startconversation', $params, 'post');

        if ($res && isset($res['id'])) {
            return true;
        }

        return false;
    }