public function sendFile($filePath, $oauth_token)
    {
        $result = $this->call('file.upload', [], $oauth_token);
        $timeout = $this->timeout;
        $this->timeout = null;
        $result = json_decode($this->httpRequest($result['upload_url'], ['file' => '@' . $filePath]), true);
        $this->timeout = $timeout;

        return $result['url'];
    }