public function _savePageSource($filename)
    {
        if (!isset($this->webDriver)) {
            $this->debug('WebDriver::_savePageSource method has been called when webDriver is not set');
            return;
        }
        try {
            file_put_contents($filename, $this->webDriver->getPageSource());
        } catch (\Exception $e) {
            $this->debug('Unable to retrieve source page from Selenium : ' . $e->getMessage());
        }
    }