public function checkVoucherAvailability($aVouchers, $dPrice)
    {
        $this->_isAvailableWithSameSeries($aVouchers);
        $this->_isAvailableWithOtherSeries($aVouchers);
        $this->_isValidDate();
        $this->_isAvailablePrice($dPrice);
        $this->_isNotReserved();

        // returning true - no exception was thrown
        return true;
    }