You can do that, but: - Even in this example, I would assume that branch A is more often executed. So the zero cost optimization (which is about branch A) woul

You can do that, but: - Even in this example, I would assume that branch A is more often executed. So the zero cost optimization (which is about branch A) would improve this code performance. - I would argue, code which uses `some_dict.get(key, fallback)` or explicitly check `if key in some_dict: ...` is both more clean and more Pythonic. See also e.g.: https://mail.python.org/pipermail/python-dev/2014-March/133118.html https://mail.python.org/pipermail/python-dev/2014-March/1331...