public static function getTimestampFromReadableDate($dateString, $offsetHours = 0)
 {
     // get datetime object from site timezone
     try {
         $datetime = new DateTime($dateString, new DateTimeZone(DateUtilities::wp_get_timezone_string()));
     } catch (Exception $e) {
         $datetime = new DateTime("2000-01-01", new DateTimeZone(DateUtilities::wp_get_timezone_string()));
     }
     // add the offsetHours
     // $date->add(new DateInterval('P10D'));
     // $datetime->add( new DateInterval( "PT".$offsetHours."H" ) ); // only PHP 5.3.x +
     if ($offsetHours > 0) {
         $datetime->modify('+' . $offsetHours . ' hours');
     }
     // get the unix timestamp (adjusted for the site's timezone already)
     $timestamp = $datetime->format('U');
     return $timestamp;
 }