code: public String getStandardResponseAttachment(String id, String documentId) throws ApiException {
          ApiResponse<String> resp = getStandardResponseAttachmentWithHttpInfo(id, documentId);
          return resp.getData();
      }
docs: Get the attachment of the Standard Response
  Get the attachment of the Standard Response specified in the documentId path parameter
  @param id id of the Standard Response (required)
  @param documentId id of document to get (required)
  @return String
  @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body