All I remember clearly still is the baffled frustration, like you feel when a C compiler optimizes out undefined behavior you didn't know about. I was using nam

All I remember clearly still is the baffled frustration, like you feel when a C compiler optimizes out undefined behavior you didn't know about. I was using namedtuple in generally this kind of way: https://github.com/darius/tinyhiss/blob/master/terp.py#L90 https://github.com/darius/tinyhiss/blob/master/terp.py#L90 (this was a trampolined interpreter for a dialect of Smalltalk). One thing that could happen is, when you might expect to see a type error if you take one of these objects x and mistakenly write x[0], it'd just continue on with some field value. Or if you mistakenly try to iterate over x, you can. Or maybe you were generically walking a tree of objects and didn't intend for an instance of one of these classes to have children. The bafflement I ran into was weirder than these; maybe it had to do with the fact that inheritance was mixed in here too? And I think I'd defined `__getitem__` in some of these classes one of those times. Sorry I can't remember more. To write https://github.com/darius/tailbiter https://github.com/darius/tailbiter I had to know quite a bit about Python, but it's a big language! It was a mistake to assume I could use namedtuple as just a convenient way to define a struct type without grokking all its details.