Um.  If they aren't expected to understand how to write this code, why isn't it being provided to them as a canned function as part of the test environment?

To succeed in getting something like this added, I suspect you will need to show that it has more general utility, or there is something analogous that can be added that has more general utility.  I recommend starting a discussion on the python-ideas mailing list.

By the way, if I needed this in my code, I'd write:

  with open(file_name, newline="") as csvfile:
      my_list = list(csv.reader(csvfile))

  with open(file_name, 'w', newline="") as csvfile:
      csv.writer(csvfile).writerows(my_list)

Only if I needed it more than once would I bother wrapping it in a function.