How do you test for whether a csv file is created or not using python unittest?

I have been following this video- https://www.youtube.com/watch?v=6tNS--WetLI for a tutorial on unittest python. But this and all other sources give a very simple example. Can someone please guide me to the solution or more sources to learn this?

I have already used the is_file() function. I want to do this with unittest.