[Python-Dev] Questions about sets.py

[Greg Ewing]

Guido van Rossum <guido@python.org>:

> But in order to be a good
> citizen in the world of binary operators, __or__ should not raise
> TypeError;
> 
> if the other argument implements __ror__, union()
> will acquire this ability.

Another possible reason is so that if a subclass
overrides __or__, union() will get the new behaviour
too.

Greg Ewing, Computer Science Dept, +--------------------------------------+
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