Message109944
In this case, the concrete class is the one missing a method.
Concrete classes are allowed to provide more features than the corresponding ABC, but the converse is not true to the best of my knowledge.
dict_keys .register()s as supporting the Set ABC, so it does not automatically pick up the method through inheritance. Put another way:
>>> # dict_keys provides the Set ABC API
>>> isinstance({}.keys(), collections.Set)
True
>>> # The Set ABC provides isdisjoint
>>> hasattr(collections.Set, 'isdisjoint')
True
>>> # Ergo, dict_keys should provide isdisjoint ... but it doesn't
>>> hasattr({}.keys(), 'isdisjoint')
False
See also Issue9213 for another case where a concrete class is missing a method provided by an ABC it claims to support.
I sort of wonder if .register() should verify that the concrete class provides all of the methods of the ABC. |
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Date |
User |
Action |
Args |
2010-07-10 23:42:25 | stutzbach | set | recipients:
+ stutzbach, rhettinger, eric.araujo |
2010-07-10 23:42:25 | stutzbach | set | messageid: <1278805345.36.0.729772848157.issue9212@psf.upfronthosting.co.za> |
2010-07-10 23:42:24 | stutzbach | link | issue9212 messages |
2010-07-10 23:42:23 | stutzbach | create | |
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