public static function getNbJours($startDate = null, $endDate = null, $joursOuvres = true)
    {
        $nbJours = false;
        if (is_numeric($startDate) && is_numeric($endDate)) {
            $start = new Datetime($startDate);
            $start->set_jours_ouvres($joursOuvres);
            $end = new Datetime($endDate);
            $end->set_jours_ouvres($joursOuvres);
            $nbJours = ($joursOuvres) ? $start->diff($end)->jo : $start->diff($end)->j;
        }
        
        return $nbJours;
    }