[ShahadatTest]

acontainer() accepts arbitrary collection factories at runtime, but its three overloads reject frozenset and custom functions. Add a generic factory overload that retains the concrete return type. The regression test checks both runtime results and inferred types for frozenset[int] and a summary dict. Built-in tuple/list/set overloads remain first and keep their existing precision.

Before: basedpyright rejects both supported custom-container calls (8 diagnostics). After: whole-project mypy and basedpyright pass; pyrefly reports 0 errors. Python 3.10/3.12: 429 passed, 5 IANA-timezone skips and 100% statement/branch coverage each. Ruff lint/format and diff checks pass. Test environments set asyncio_default_fixture_loop_scope=function explicitly.

AI assistance: OpenAI Codex found this by code inspection, implemented and tested it at the account owner’s request ("15 TA koro aro"). No personal production incident or independent human review is claimed.

[wolph]

Thank you for the fix :) The implementation already took any factory, so the overloads were the only thing in the way. I've added a changelog entry on top in 237a670, beyond that it's merged as it was. I'm working on a new release (4.2.0), should be out soon :)

[wolph]

I've created a new release (v4.2.0) which includes your fix, thanks again for the help :)