code: protected RestAdapter getRestAdapterApiFour() {
          if (restAdapterApiFour == null) {
              RestAdapter.Builder builder = newRestAdapterBuilder();
              builder.setEndpoint(API_V4_URL);
  
              if (isDebug) {
                  builder.setLogLevel(RestAdapter.LogLevel.FULL);
              }
  
              restAdapterApiFour = builder.build();
          }
  
          return restAdapterApiFour;
      }
docs: Return the current {@link retrofit.RestAdapter} instance for v4 API calls (currently search only). If none exists
  (first call), builds a new one.
  
  <p> When building, sets the endpoint and log level.