* @return execution result
*/
public <R> R execute(MailChimpMethod<R> method) throws IOException, MailChimpException {
final Gson gson = MailChimpGsonFactory.createGson();
JsonElement result = execute(buildUrl(method), gson.toJsonTree(method), method.getMetaInfo().version());
if(result.isJsonObject()) {
JsonElement error = result.getAsJsonObject().get("error");
if(error != null) {
JsonElement code = result.getAsJsonObject().get("code");
throw new MailChimpException(code.getAsInt(), error.getAsString());