Let me just address this point: 2018-07-19 20:36 GMT+02:00 Brendan Barnwell <brenbarn@brenbarn.net>:
As far as I can see, these null-coalescing operators would break that model. The PEP doesn't seem to provide for a "real" magic method allowing users to override the actual behavior of the method. (You can only override __has_value__ to hook into it, but not define by fiat what A ?? B does, as you can with other operators.) And I think the reason for this is that the operator itself is too specific, much more specific in semantics than other operators. (I had similar doubts about adding the matrix-multiplication operator @.)
I think the actual reason is that it is a short-cutting operator, and none of the shortcutting operators (and, or, if/else) have an associated method. They cannot have, since they induce a non-standard evaluation order, hence their effect cannot be emulated with a method invocation. Stephan