"is" and "=="

[Erik Max Francis]

Terry Reedy wrote:

> That is one of the few uses, and is recommended over 'x == None'.  'x
> is True' would be except that 'x' and 'x is True' have the same
> logical value and thus the extra test is useless.  Similarly for 'not
> x' and 'x is False' (the former might also be faster).

In fact, the extra test is worse than useless, since it explicitly
excludes any true (or false) value other than the literal Boolean True
(or False).

-- 
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