This one isn't just the naming: Python 3 has a concept of an except-handler block *and* a setup-except block. (That is, byte_SETUP_EXCEPT works the same way across versions.)  In 2.x, POP_EXCEPT requires a setup-except block; in 3.x it's looking for an except-handler.  The except-handler gets pushed on to the block stack [here](https://github.com/akaptur/byterun/blob/py3-exceptions-and-with/byterun/pyvm2.py#L265).