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;
}