public function get_objects($type, $param_options = array()) {
    if ($this->cache) {
      $signature = $this->createSignature($type . '/', $param_options);
      if ($this->cache->contains($signature)) {
        return $this->cache->fetch($signature);
      }
    }

    $resp = $this->call($type, $param_options);
    $result = $this->parse_result($resp['data']);

    if ($this->cache) {    
      $this->cache->save($signature, $result);
    }

    return $result;
  }