code: public ApiSuccessResponse unsubscribe(String subscriptionId) throws ApiException {
          ApiResponse<ApiSuccessResponse> resp = unsubscribeWithHttpInfo(subscriptionId);
          return resp.getData();
      }
docs: Delete a subscription
  Delete the specified subscription by closing all its statistics.
  @param subscriptionId The unique ID of the subscription. (required)
  @return ApiSuccessResponse
  @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body