Re: [Python-ideas] add a list.swap() method

Nick Coghlan wrote:

Then again, maybe we just need to document this behaviour as a trap of subclassing the mutable builtins: make sure to override *all* the mutating methods in subclasses, not just the special methods.

I would never have imagined things were otherwise. This is a general principle that applies to all classes, whether builtin or not: unless explicitly documented, you can't make any assumptions about how methods call each other internally. -- Greg