I assume you are following this example, Lidar 3-D Object Detection Using PointPillars Deep Learning, as I see that this example uses the mentioned helper function.
As the helper function is part of the live script from the example, you'll be able to run it only inside the live script.
1. Open the live script using the following command:
openExample('deeplearning_shared/Lidar3DObjectDetectionUsingPointPillarsExample')
2. Click on the code snippet in the Download Lidar Data Set section.
3. Click on 'Run Section' on the toolstrip at the top. This should let you run this particular section.
If you'd like to use the helper function outside the live script, I'd suggest you create an individual function script and copy the content of the helperDownloadPandasetData in this file and save it in your working directory.
