Methods that mutate their argument typically return None, to avoid confusing them with methods that return copies; If you both mutate and return a copy it is easy to end up with shared objects in place you actually don't want them
even = [2,4,6] odd = [1,3,5] all = odd.extend(even)
... oops.
--
M
On Wed, 3 Mar 2021 at 12:43, Hans Ginzel
Please, is there a reason why extend() method does not return self?
a = [1,2].extend((3,4)) a type(a)
b = [1,2] b.extend((3,4)) b [1, 2, 3, 4]
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