3 ms·

I'd almost consider this a subtle bug? None of the other += operators returns a value.

• masklinn 7y ago
  > I'd almost consider this a subtle bug? It's not exactly a bug but it is a somewhat unexpected behaviour and IIRC Guido regretted that list.__iadd__ was overridden this way. > None of the other += operators returns a value. It's not the operator which returns a value, it's the data model hook. The data model requires that it return a value: https://docs.python.org/3/reference/datamodel.html?#object.__iadd__ https://docs.python.org/3/reference/datamodel.html?#object._... > These methods should attempt to do the operation in-place (modifying self) and return the result (which could be, but does not have to be, self). Really the issue is that the "in-place" hooks are simply weird.