If you had to judge someones level of Python understand in just 3 questions, what would you ask?
This is pretty much the same as for any language.

What projects have you done with Python?
What is your favorite Python reference?
Have you worked with other people on code written in Python?

That's how I would judge. If I wanted to test, it would depend on whether I were looking for someone to write in 2.x or 3.x. Since I'm familiar with the 2.x stuff...

How would you create a list containing the result of [insert operation] on another list?
How would you do the above if you cared about memory usage?
What tool do you use to debug your Python code?

CW'd because the question should be.
Top 3 questions to test someones Python level, what would they be?