Removing numpy.array_api import

[rgommers]

Hi, I noticed through code search that there are a few comments in this repo that reference numpy.array_api and (more importantly) one import:

cubed/cubed/array_api/data_type_functions.py

Line 4 in 76ea07e

from numpy.array_api._typing import Dtype

I wanted to give you a heads up that in NumPy 2.0 that import will break. Because we'll have support for the array API standard in the main numpy namespace, the numpy.array_api submodule is being removed (see numpy/numpy#25911).

For testing purposes, https://github.com/data-apis/array-api-strict can be used. The Dtype type annotation you're using is probably best vendored: https://github.com/numpy/numpy/blob/maintenance/1.26.x/numpy/array_api/_typing.py#L55-L66

[tomwhite]

Thanks for the heads up @rgommers!

That code and all the other places with comments referencing numpy.array_api are all concerned with dtype functions. Now that we are using Array API compliant backend array libraries (see https://github.com/cubed-dev/cubed/blob/main/cubed/backend_array_api.py) we should delegate these functions to the backend library.