public function parentKeysToErrorName($parent_keys) {
		$result = [];
		if (!is_array($parent_keys)) {
			$parent_keys = [$parent_keys];
		}
		foreach ($parent_keys as $v) {
			if (empty($result)) {
				$result[] = $v;
			} else {
				$result[] = '[' . $v . ']';
			}
		}
		return implode('', $result);
	}