Response message for the ImportProductSets method.
This message is returned by the
method in the returned
reference_images The list of reference_images that are imported successfully.
statuses The rpc status for each ImportProductSet request, including
both successes and errors.
The number of statuses here matches the number of lines in
the csv file, and statuses[i] stores the success or failure
status of processing the i-th line of the csv, starting from