public function getMetadata($block, $metadataKey)
{
if (!$block instanceof Block) {
throw new \InvalidArgumentException("Object must be a Block");
}
if ($block->getLevel() === $this->owningLevel) {
return parent::getMetadata($block, $metadataKey);
} else {
throw new \InvalidStateException("Block does not belong to world " . $this->owningLevel->getName());
}
}