# PEP 713: Callable Modules

**URL:** <https://discuss.python.org/t/pep-713-callable-modules/26127>\
**Category:** PEPs\
**Created:** [April 23, 2023, 8:31pm UTC](https://discuss.python.org/t/pep-713-callable-modules/26127 "2023-04-23T20:31:03Z")\
**Posts on this page:** 1\
**Showing post:** 40

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**Author:** ![oscarbenjamin](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/oscarbenjamin/32/1209_2.png) [@oscarbenjamin](https://discuss.python.org/u/oscarbenjamin)\
**Post date:** [April 26, 2023, 6:46pm UTC](https://discuss.python.org/t/pep-713-callable-modules/26127/40 "2023-04-26T18:46:18Z")

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> [@njs](#):
>
> This isn’t necessarily a blocker – we still added the special ` __getattr__ ` and ` __setattr__ ` support despite those already being possible through ` __class__ ` assignment.

Is there ` __setattr__ ` support?

There is a parallel thread proposing to add that:

> [@Extend PEP 562 with \_\_setattr\_\_ for modules?](https://discuss.python.org/t/extend-pep-562-with-setattr-for-modules/25506):
>
> Since CPython 3.5 it’s possible to customize setting module attributes by setting \_\_class\_\_ attribute. Unfortunately, this coming with a measurable speed regression for attribute access: $ cat b.py x = 1 $ python -m timeit -r11 -s 'import b' 'b.x' 5000000 loops, best of 11: 48.8 nsec per loop $ cat c.py import sys, types x = 1 class \_Foo(types.ModuleType): pass sys.modules[\_\_name\_\_].\_\_class\_\_ = \_Foo $ python -m timeit -r11 -s 'import c' 'c.x' 2000000 loops, best of 11: 131 nsec per loop For r…

As mentioned there one downside of setting ` __class__ ` is that it slows down all attribute access and reading attributes from a module is very common (`np.sin(...)` etc).

> [@njs](#):
>
> it would also be nice if we came out of the discussion with more general principles about which module dunders are worth special-casing and which aren’t.

In ordinary Python code modules are namespaces and their interface is only expected to provide attributes. The ` __getattr__ ` proposal (PEP 562) has a clear motivation around accessing deprecated attributes. PEP 562 also added ` __dir__ ` which is for listing attributes. The ` __setattr__ ` proposal in the other thread is motivated by wanting to disallow (or warn about) setting attributes in cases where it could be a likely user error to do so. I don’t see why any special support should be added to encourage defining modules that have unusual features besides attribute access: most other operations should generally be expected to give `TypeError`.

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_[View the full topic](https://discuss.python.org/t/pep-713-callable-modules/26127)._