Message257057
As mentioned in #25958, Guido pointed out on -ideas that `__hash__ = None` is already the standard way to declare a class unhashable, and it's recognized by `collections.abc.Hashable`.
Doing `__reversed__ = None` does make `reversed(m)` raise a `TypeError` (although with a description saying "'NoneType' is not callable", which isn't quite as nice a description, but probably good enough).
So, I think `Mapping` should set `__reversed__ = None`, rather than setting it to a method that raises `TypeError`. (If we need something more general, that's for #25958 and/or Serhiy's typechecking bug.) |
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Date |
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2015-12-26 23:32:13 | abarnert | set | recipients:
+ abarnert, gvanrossum, rhettinger, terry.reedy, r.david.murray, serhiy.storchaka, abarry, curioswati |
2015-12-26 23:32:13 | abarnert | set | messageid: <1451172733.46.0.245413628278.issue25864@psf.upfronthosting.co.za> |
2015-12-26 23:32:13 | abarnert | link | issue25864 messages |
2015-12-26 23:32:13 | abarnert | create | |
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