docs: public Result<Series> getSeries(String key) {
      checkNotNull(key);
  
      URI uri = null;
      try {
        URIBuilder builder = new URIBuilder(String.format("/%s/series/key/%s/", API_VERSION, urlencode(key)));
        uri = builder.build();
      } catch (URISyntaxException e) {
        String message = String.format("Could not build URI with inputs: key: %s", key);
        throw new IllegalArgumentException(message, e);
      }
  
      HttpRequest request = buildRequest(uri.toString());
      Result<Series> result = execute(request, Series.class);
      return result;
    }