public function process()
    {
        $operands = $this->getOperands();

        if ($operands->containsNull() === true) {
            return null;
        }

        if ($operands->exclusivelyMultipleOrOrdered() === false) {
            $msg = "The Random operator only accepts values with multiple or ordered cardinality.";
            throw new OperatorProcessingException($msg, $this, OperatorProcessingException::WRONG_CARDINALITY);
        }

        $operand = $operands[0];
        $maxIndex = count($operand) - 1;

        return $operand[mt_rand(0, $maxIndex)];
    }