Ethan Furman added the comment: https://docs.python.org/2/reference/datamodel.html#object.__iadd__ ------------------------------------------------------------------ [...] 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). If a specific method is not defined, the augmented assignment falls back to the normal methods. For instance, to execute the statement x += y, where x is an instance of a class that has an __iadd__() method, x.__iadd__(y) is called. If x is an instance of a class that does not define a __iadd__() method, x.__add__(y) and y.__radd__(x) are considered, as with the evaluation of x + y.
------------------------------------------------------------------- Returning NotImplemented still allows a TypeError to be raised, is subclass friendly, and is the way Python is designed. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue22766> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
