code: public FutureData<ManagedSourceList> get(ManagedDataSourceType type, int page, int perPage) {
          FutureData<ManagedSourceList> future = new FutureData<>();
          ParamBuilder b = newParams();
          if (type != null) {
              b.put("source_type", type.value());
          }
          if (page > 0) {
              b.put("page", page);
          }
          if (perPage > 0) {
              b.put("per_page", perPage);
          }
          URI uri = b.forURL(config.newAPIEndpointURI(GET));
          Request request = config.http().
                  GET(uri, new PageReader(newRequestCallback(future, new ManagedSourceList(), config)));
          performRequest(future, request);
          return future;
      }
docs: /*
  Get manage sources for the given type