[issue17626] set's __isub__ doesn't support non-sets.

[Terry J. Reedy]

Terry J. Reedy added the comment:

Intentional and documented.

"5.7. Set Types — set, frozenset
...
Note, the non-operator versions of union(), intersection(), difference(), and symmetric_difference(), issubset(), and issuperset() methods will accept any iterable as an argument. In contrast, their operator based counterparts require their arguments to be sets. ..."

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nosy: +terry.reedy
resolution:  -> invalid
status: pending -> closed
versions: +Python 3.4 -Python 3.2

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue17626>
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