public function invalidate($namespaceId)
    {
        $namespace = $this->fetch($namespaceId);

        if (false === $namespace) {
            return false;
        }

        $newNamespace = rand(0, 10000);
        // @codeCoverageIgnoreStart
        while ($namespace === $newNamespace) {
            $newNamespace = rand(0, 10000);
        }

        // @codeCoverageIgnoreEnd
        return $this->save($namespaceId, $namespaceId . '_' . $newNamespace .'_', 0);
    }