Service/Calc/Forecast/Plain.php
private function getPeriod($requested)
    {
        $month = substr($requested, 0, 6);
        $begin = $this->hlpPeriod->getPeriodFirstDate($month);
        $end = $this->hlpPeriod->getPeriodLastDate($month);
        $result = [$begin, $end];
        return $result;
    }
private function getPeriod($requested)
    {
        $month = substr($requested, 0, 6);
        $begin = $this->hlpPeriod->getPeriodFirstDate($month);
        $end = $this->hlpPeriod->getPeriodLastDate($month);
        $result = [$begin, $end];
        return $result;
    }
Return 2 dates (period being/end): first day of the month and today.

@param string $requested 'YYYY', 'YYYYMM' or 'YYYYMMDD'
@return array