private function addRemovedIds()
    {
        if (!$ids = $this->container->getRemovedIds()) {
            return '';
        }
        if ($this->asFiles) {
            $code = "require \$this->containerDir.\\DIRECTORY_SEPARATOR.'removed-ids.php'";
        } else {
            $code = '';
            $ids = array_keys($ids);
            sort($ids);
            foreach ($ids as $id) {
                $code .= '            '.$this->doExport($id)." => true,\n";
            }

            $code = "array(\n{$code}        )";
        }

        return <<<EOF

    public function getRemovedIds()
    {
        return {$code};
    }

EOF;
    }