Fix ZZ.cartesian_product(...)

[nthiery]

This fails due to an inadvertent change introduced by #12959:

sage: ZZ.cartesian_product(GF(2), NN)
Traceback (most recent call last)
...
AttributeError: type object 'sage.rings.integer_ring.IntegerRing_class' has no attribute 'CartesianProduct'

This ticket reverts this change and adds a doctest.

Depends on #16280
Depends on #16288
Depends on #16269

CC: @sagetrac-sage-combinat @nathanncohen @videlec

Component: combinatorics

Author: Nicolas M. Thiéry

Branch/Commit: c9a7e67

Reviewer: Nathann Cohen

Issue created by migration from https://trac.sagemath.org/ticket/16289

[nthiery]

Branch: u/nthiery/16269-optimized

[nthiery]

Changed branch from u/nthiery/16269-optimized to u/nthiery/16289/fix_zz_cartesian_product

[nthiery]

Last 10 new commits:

aa07ba1	trac #16269: Working around "officially not a bug"
d22e245	trac #16269: missing __iter__
f262faa	trac #16269: Merged with 6.2.rc1
338cc5b	trac #16269: Reviewer's remarks
8ac32c2	#16280: Fix call for FiniteEnumeratedSet's of plain Python objects
4e27454	#16280: Trivial doctest fixes
f67d82e	trac #16269: Merged with #16280
0a54b68	Trac 16269: little improvements + line folding in the doctest output
b5ad803	Trac 16269 (or follow up): optimize CartesianProduct._cartesian_product_of_elements
c9a7e67	#16289: Fix ZZ.cartesian_product(...)

[nthiery]

Commit: c9a7e67

[tscrim]

Dependencies: #16280

[nathanncohen]

comment:5

This branch apparently includes #16269 as a dependency... But perhaps that is not a problem anyway as it is already reviewed ?

Nathann

[nathanncohen]

comment:6

........................... and this branch also depends on the commit labeled with "rac 16269 (or follow up)" which is actually not #16269 but #16288...

Nathann

[nathanncohen]

comment:7

(I set the dependencies that appear in the branch, please update it if you rewrite the branch as some of these dependencies are not necessary. But of course possibly we don't care for as long as everything gets reviewed)

[nathanncohen]

Changed dependencies from #16280 to #16280, #16288, #16269

[nthiery]

comment:8

Replying to @nathanncohen:

(I set the dependencies that appear in the branch, please update it if you rewrite the branch as some of these dependencies are not necessary. But of course possibly we don't care for as long as everything gets reviewed)

There actually is a small semantic dependency upon #16269 since it changes the output of one of the doctests of this ticket. For #16288, oh well. Let's just keep the branch as it is. As you say we don't really care since everything is positive reviewed or close enough to be so.