python-review

## Python review guidelines This project uses Python for the SDK (`python/cog/`) which defines the predictor interface, type system, and HTTP/queue server. ### What linters already catch (skip these) ruff handles pycodestyle (E), Pyflakes (F), isort (I), warnings (W), bandit (S), bugbear (B), and annotations (ANN). Don't flag issues these would catch. ### What to look for **Type annotations** - Required on all function signatures - Use `typing_extensions` for backward compatibility - Avoid `Any` where a concrete type is possible - Check that type annotations actually match runtime behavior **Compatibility** - Must support Python 3.10 through 3.13 - Watch for syntax/stdlib features only available in newer versions - `from __future__ import annotations` if using newer annotation syntax **Error handling** - No bare `except:` or `except Exception:` that swallows everything - Exceptions should have descriptive messages - Resource cleanup with context managers, not try/finally when avoidable **Async patterns** - Tests use pytest-asyncio -- async tests need proper fixtures - Watch for blocking calls inside async functions - Proper cleanup of async resources (aclose, async context managers) **Predictor interface** - `base_predictor.py` is the core interface -- changes here affect all users - `types.py` defines input/output types -- check backward compatibility - Server code in `python/cog/server/` handles HTTP -- watch for request handling bugs **Testing** - Uses pytest with fixtures - tox runs tests across Python 3.10-3.13 - Test isolation: don't rely on global state or test ordering