Run Python script with arguments or return values in ArcGIS Workflow

I found out how to run Python script in custom Step in ArcGIS Workflows. It is possible if I use Executable Execution Type, as executable to run is called python.exe and argument is path to the script. Like this:

But I want to find out how to add some other arguments, like layer names that are created during previous Workflow Steps.

How can I get Return Value from some Step as an argument into this Python script?