code: public String deleteImage(String listId, String imageId) {
          return deleteImageWithServiceResponseAsync(listId, imageId).toBlocking().single().body();
      }
docs: Deletes an image from the list with list Id and image Id passed.
  
  @param listId List Id of the image list.
  @param imageId Id of the image.
  @throws IllegalArgumentException thrown if parameters fail the validation
  @throws APIErrorException thrown if the request is rejected by server
  @throws RuntimeException all other wrapped checked exceptions if the request fails to be sent
  @return the String object if successful.