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| From | Ian Kelly <ian.g.kelly@gmail.com> |
| Date | Mon, 3 Aug 2015 02:26:48 -0800 |
| Subject | Re: Python 3 May Become Relevant Now |
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On Mon, Aug 3, 2015 at 1:58 AM, Jean-Michel Pichavant <jeanmichel@sequans.com> wrote: > But if I get things right, with python 3.5 type hint checker, I'd be screwed, as it is spefificaly designed to track this kind of "problem". > What's the use of None then ? Any method returning None can only return None or suffer the type checker retribution. > > I don't get it. This is where you would use optional types. Optional[List[X]] is a shorthand for the type Union[List[X], None]. In fact static type checking can be quite useful in this sort of case. If you return Optional[List[X]] in one place, and you have some other method that takes in the value but simply indicates that it takes List[X], then the static checker will flag that as an error, and you'll know that a part of your code likely isn't handling the None case correctly.
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Re: Python 3 May Become Relevant Now Ian Kelly <ian.g.kelly@gmail.com> - 2015-08-03 02:26 -0800
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