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| From | Terry Reedy <tjreedy@udel.edu> |
| Subject | Re: verify the return value of a function |
| Date | Fri, 20 Jan 2012 15:42:45 -0500 |
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On 1/20/2012 10:07 AM, Steven D'Aprano wrote: > What should be avoided, when possible, is over-reliance on isinstance > checks instead of protocol or interface checks. For example, don't check > for a list if your function doesn't *need* a list but would be happy with > a tuple or some other sequence. In other words, do not use isinstance to artificially limit the input domain of a function. The generic or polymorphic nature of (builtin) operators and functions is a major feature of Python. On the other hand, the output range of a function is typically much more limited as to type. Complete testing requires testing the specified output type. For instance, sorted(iterable) is documented as producing a sorted list, so 'type(output) is list' is an appropriate test. -- Terry Jan Reedy
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Re: verify the return value of a function Jean-Michel Pichavant <jeanmichel@sequans.com> - 2012-01-20 11:13 +0100
Re: verify the return value of a function Mel Wilson <mwilson@the-wire.com> - 2012-01-20 08:53 -0500
Re: verify the return value of a function Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-20 15:07 +0000
Re: verify the return value of a function Terry Reedy <tjreedy@udel.edu> - 2012-01-20 15:42 -0500
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