setAllowNewKeys example

if (false !== $this->addDefaultChildren) {
                $node->setAddChildrenIfNoneSet($this->addDefaultChildren);
                if ($this->prototype instanceof static && !isset($this->prototype->prototype)) {
                    $this->prototype->addDefaultsIfNotSet();
                }
            }

            $this->prototype->parent = $node;
            $node->setPrototype($this->prototype->getNode());
        }

        $node->setAllowNewKeys($this->allowNewKeys);
        $node->addEquivalentValue(null, $this->nullEquivalent);
        $node->addEquivalentValue(true, $this->trueEquivalent);
        $node->addEquivalentValue(false, $this->falseEquivalent);
        $node->setPerformDeepMerging($this->performDeepMerging);
        $node->setRequired($this->required);
        $node->setIgnoreExtraKeys($this->ignoreExtraKeys, $this->removeExtraKeys);
        $node->setNormalizeKeys($this->normalizeKeys);

        if ($this->deprecation) {
            $node->setDeprecated($this->deprecation['package'], $this->deprecation['version'], $this->deprecation['message']);
        }