Jackalope\Node::getDefinition PHP Method

    public function getDefinition()
    {
        $this->checkState();
        if ('rep:root' === $this->primaryType) {
            throw new NotImplementedException('what is the definition of the root node?');
        }
        if (empty($this->definition)) {
            $this->definition = $this->findItemDefinition(function (NodeTypeInterface $nt) {
                return $nt->getChildNodeDefinitions();
            });
        }
        return $this->definition;
    }