code: public ApiResponse<SubscriptionEnvelope> validateSubscriptionWithHttpInfo(String subId, ValidationCallbackInfo validationCallbackRequest) throws ApiException {
          com.squareup.okhttp.Call call = validateSubscriptionValidateBeforeCall(subId, validationCallbackRequest, null, null);
          Type localVarReturnType = new TypeToken<SubscriptionEnvelope>(){}.getType();
          return apiClient.execute(call, localVarReturnType);
      }
docs: Validate Subscription
  Validate Subscription
  @param subId Subscription ID. (required)
  @param validationCallbackRequest Subscription validation callback request (required)
  @return ApiResponse&lt;SubscriptionEnvelope&gt;
  @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body