public function seekFirstPage() { if ($this instanceof self) { $index_key = $this->getConfig()['index_key']; if (isset($this->children[$index_key])) { return $this->children[$index_key]; } foreach ($this->children as $node_key => $node) { if ($node instanceof Content) { return $node; } if ($node instanceof self && strpos($node->getUri(), '.') !== 0 && ($childNode = $node->seekFirstPage())) { return $childNode; } } } return null; }