private function checkIfSetterFunction(int $classPosition, File $file, int $methodPosition): bool
    {
        $isSetter = false;
        $methodName = $file->getDeclarationName($methodPosition);

        if (substr($methodName, 0, 3) === 'set') {
            // We define in our styleguide, that there is only one class per file!
            $properties = (new PropertyHelper(new FileDecorator($file)))->getProperties(
                $file->getTokens()[$classPosition]
            );

            // We require camelCase for methods and properties,
            // so there should be an "lcfirst-Method" without set-prefix.
            $isSetter = in_array(lcfirst(substr($methodName, 3)), $properties, true);
        }

        return $isSetter;
    }