preferred syntax for list extend?

[Bernhard Herzog]

aahz at pythoncraft.com (Aahz) writes:

> Heh. That's because of the way __iadd__ works. Immutable objects must
> return a new object with __iadd__;

Why would you want to implement __iadd__ for immutable objects? Just
__add__ (and maybe __radd__) should be enough.

> mutable objects *MAY* return self (and usually do).

Wouldn't it have been enough to assume that __iadd__ always, if defined,
modifies the object in place?

   Bernhard

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