protected function checkIfSingleInSetOrEmpty(
        $fieldName,
        $canUseFlexforms,
        $sheet,
        $explanation,
        array $allowedValues
    ) {
        if ($this->objectToCheck->hasConfValueString($fieldName, $sheet)) {
            $value = $this->objectToCheck->getConfValueString($fieldName, $sheet);
            $this->checkIfSingleInSetOrEmptyValue(
                $value,
                $fieldName,
                $canUseFlexforms,
                $explanation,
                $allowedValues
            );
        }
    }