--- icon: dot title: Undefined Behaviour --- These are the undefined behaviours of pkpy. The behaviour of pkpy is undefined if you do the following things. 1. Delete a builtin object. For example, `del int.__add__`. 2. Call an unbound method with the wrong type of `self`. For example, `int.__add__('1', 2)`. 3. Use goto statement to jump out of a context block.