How to use base parameter within a Synapse Notebook Pipeline activity?

Question

I'm trying to use a base parameter (parameter_test )that I have for a notebook activity and reference that parameter within my notebook itself. I'm using pyspark, and need to pass in this parameter and set it to a variable within my notebook as shown here:

variable = parameter_test

The issue is that I cannot seem to find the syntax for how to do this. And I know for a fact that the notebook activity is reading in the parameter value correctly because it appears in the input json for the activity, I just need to figure out how to reference it.