"Speaker: Amy Hanlon Many of us have experienced a ""wat"" in Python - some behavior that totally mystifies us. We'll look at three areas where wats arise - identity, mutability, and scope. For each of these three topics, we'll look at some common surprising behaviors, investigate the cause of the behaviors, and cover some practical tips on how to avoid related bugs. Slides can be found at: https://speakerdeck.com/pycon2015 and https://github.com/PyCon/2015-slides"