public function setWorkingDaysInMonth(\DateTime $lngDate, $inclCatholicEaster = false)
    {
        $holidaysInGivenYear = $this->setHolidays($lngDate, $inclCatholicEaster);
        $thisMonthDayArray   = $this->setMonthAllDaysIntoArray($lngDate);
        $workingDays         = 0;
        foreach ($thisMonthDayArray as $value) {
            if (!in_array(strftime('%w', $value), [0, 6]) && !in_array($value, $holidaysInGivenYear)) {
                $workingDays += 1;
            }
        }
        return $workingDays;
    }