public function validateDateRange($dateFrom, $dateTo)
    {
        if (!$this->validateDate($dateFrom) || !$this->validateDate($dateTo)) {
            return 'From or To date is not a valid date.';
        }
        if (strtotime($dateFrom) > strtotime($dateTo)) {
            return 'To Date cannot be earlier then From Date.';
        }
        return false;
    }