Error in description of __iadd__() method

[Flyagin]

Documentation

In the documentation, in the description of __iadd__() and other similar methods implementing the augmented arithmetic assignments (+=, -=, *=, /=, //=, %=, **=, <<=, >>=, &=, ^=, |=), the following contradiction (as it seems to me) occurs:

1. "These methods should attempt to do the operation in-place (modifying self)"
2. "For instance, if x is an instance of a class with an __iadd__() method, x += y is equivalent to x = x.__iadd__(y)"

As far as I understand, if __iadd__() method attempts to do the operation "in-place (modifying self)", then “x =” at the beginning of this statement:

x = x.__iadd__(y)

… is redundant.

[ericvsmith]

You left off the end of the sentence: "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)".

It can modify self, and return self. Or create a new object and return it. The point is that whether or not the type is immutable, then these operator still work.