Neos\ContentRepository\Domain\Model\NodeType::isNodeTypeAllowedByInheritanceConstraints PHP Method

    protected function isNodeTypeAllowedByInheritanceConstraints(NodeType $nodeType, array $constraints)
    {
        $constraintDistanceForTrue = null;
        $constraintDistanceForFalse = null;
        foreach ($constraints as $superType => $constraint) {
            if ($nodeType->isOfType($superType)) {
                $distance = $this->traverseSuperTypes($nodeType, $superType, 0);
                if ($constraint === true && ($constraintDistanceForTrue === null || $constraintDistanceForTrue > $distance)) {
                    $constraintDistanceForTrue = $distance;
                }
                if ($constraint === false && ($constraintDistanceForFalse === null || $constraintDistanceForFalse > $distance)) {
                    $constraintDistanceForFalse = $distance;
                }
            }
        }
        if ($constraintDistanceForTrue !== null && $constraintDistanceForFalse !== null) {
            return $constraintDistanceForTrue < $constraintDistanceForFalse ? true : false;
        }
        if ($constraintDistanceForFalse !== null) {
            return false;
        }
        if ($constraintDistanceForTrue !== null) {
            return true;
        }
        return null;
    }