public function stringToDateTime(string $string) : \DateTime
    {
        $this->logger->notice("unsupported date format, use strtotime() to build the DateTime instance : {$string}");

        if (false === strtotime($string)) {
            throw new \InvalidArgumentException('Impossible to convert date : '.$string);
        }
        $date = new \DateTime($string, $this->getFeedTimezone());
        $date->setTimezone($this->getTimezone());

        return $date;
    }