You can define widgets in your notebook in the following way (see screenshot). When databricks workflow is running it will pass all required parameters and you can use code you've provided to read these values key1=dbutils.widgets.get("Key1").
But, let's say that something went wrong and you want to debug. Than just fill parameters of widget with values and
and now you can debug without changing any code 😉

dbutils.widgets.text("param_source_schema", defaultValue="")
param_source_schema = dbutils.widgets.get("param_source_schema")