Sorry - I'm confused - is your file - s3_handling_poc.py uploaded to Databricks?

%run is for running one notebook within another Databricks notebook.

To get local Python code into Databricks - you'll need to either import your python file as a Databricks Notebook. Or you can create an egg from your python code and upload that as a library. If it's a single python file - importing it as a Databricks notebook is going to be the easier route.