docs: Example of dynamic return type in the "Python classes" guide

[daemontus]

This PR is based on the discussion for this question. It just adds a single method into the inheritance section of the class guide.

The purpose of this new example is to show how a sub-type can be instantiated dynamically within a method other than #[new]. In other words, how to "instantiate" PyClassInitializer into an actual Python object from Rust.

If you know a better way to do this, feel free to suggest an alternative example. But the reactions in the question discussion seem to indicate that the answer is not entirely obvious, hence I considered it worth including.

[daemontus]

Sure, why not :)

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On Thu, Oct 26, 2023, 17:41 Bruno Kolenbrander ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In guide/src/class.md <#3552 (comment)>: > @@ -337,10 +337,27 @@ impl SubSubClass { let super_ = self_.into_super(); // Get PyRef<'_, SubClass> SubClass::method2(super_).map(|x| x * v) } + + #[staticmethod] + fn dynamic_type(py: Python<'_>, val: usize) -> PyResult<PyObject> { What about naming this something like... ⬇️ Suggested change - fn dynamic_type(py: Python<'_>, val: usize) -> PyResult<PyObject> { + fn factory_method(py: Python<'_>, val: usize) -> PyResult<PyObject> { ...because I think that when people want something like this they'll search for the "factory" pattern. — Reply to this email directly, view it on GitHub <#3552 (review)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA23XOPPS4OGQ4MSZSWEBO3YBLRIBAVCNFSM6AAAAAA6R4BIYGVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMYTOMBQG42DENBRGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[mejrs]

Thanks!