protected function checkRegExp(
        $fieldName,
        $canUseFlexforms,
        $sheet,
        $explanation,
        $regExp
    ) {
        $value = $this->objectToCheck->getConfValueString($fieldName, $sheet);

        if (!preg_match($regExp, $value)) {
            $message = 'The TS setup variable <strong>' . $this->getTSSetupPath()
                . $fieldName . '</strong> contains the value <strong>'
                . htmlspecialchars($value) . '</strong> which isn\'t valid. '
                . $explanation;
            $this->setErrorMessageAndRequestCorrection(
                $fieldName,
                $canUseFlexforms,
                $message
            );
        }
    }