Just a little fix to make confirm work with python 3. The problem didn't appear in the tests because raw_input is always mocked.
No tests with this fix because input() is quite hard to test, as it taps directly into stdin. The fix should be simple enough to be manually checked, though.
With python 3, it defines raw_input as a simple wrapper that decode its argument before passing it to input. The decoding is needed because the arg to raw_input is encoded, and is thus of type bytes in python 3.