private function removeSplit($key, $parts)
    {
        $keys   = array();
        $keys[] = $key;
        for ($i = 0; $i < $parts; $i++) {
            $keys[] = $key.$i;
        }

        if (false === $this->memcached->deleteMulti($keys)) {
            $msg = sprintf(
                'Unable to remove split values for key "%s": %s.',
                $key,
                $this->memcached->getResultMessage()
            );

            $this->getLogger()->log(LogLevel::NOTICE, $msg);
            throw new \RuntimeException($msg);
        }
    }