public function getSpList($keys = array())
    {
        sort($keys);
        $keysString = implode(',', $keys);
        if (isset($this->serviceProvidersMetadata[$keysString])) {
            return $this->serviceProvidersMetadata[$keysString];
        }

        $this->serviceProvidersMetadata[$keysString] = $this->client->getSpList();

        return $this->serviceProvidersMetadata;
    }