docs: public <T> T handleResponse(Response response, Type returnType) throws ApiException {
          if (response.isSuccessful()) {
              if (returnType == null || response.code() == 204) {
                  // returning null if the returnType is not defined,
                  // or the status code is 204 (No Content)
                  return null;
              } else {
                  return deserialize(response, returnType);
              }
          } else {
              String respBody = null;
              if (response.body() != null) {
                  try {
                      respBody = response.body().string();
                  } catch (IOException e) {
                      throw new ApiException(response.message(), e, response.code(), response.headers().toMultimap());
                  }
              }
              throw new ApiException(response.message(), response.code(), response.headers().toMultimap(), respBody);
          }
      }