code: private static function getTimeValue($timeValue)
      {
          $saveReturnDateType = Functions::getReturnDateType();
          Functions::setReturnDateType(Functions::RETURNDATE_EXCEL);
          $timeValue = self::TIMEVALUE($timeValue);
          Functions::setReturnDateType($saveReturnDateType);
  
          return $timeValue;
      }
docs: getTimeValue.
  
  @param string $timeValue
  
  @return mixed Excel date/time serial value, or string if error