Syntax error in selected rows

OS (e.g. Win10): Mac Catalina
PsychoPy version (e.g. 1.84.x): 2020.2.6
Standard Standalone? (y/n) If not then what?:
What are you trying to achieve?:

I would like to select three rows in the condition files randomly. I have place the below code to the ‘selected rows’ and then they said there is a syntax error. Can anyone help with it? Thanks in advance!