Tutorial document

Thoughts on the tutorial document.

Basic Topics

• Set up a basic venv with a pinned mypy version. (For compatibility reasons.) Should add a note about using a current version in production.
• Annotating variables.
• Annotating functions and methods.
• Unions, using | None
• Any
• cast() and # type: ignore
• Using generics, variance
• Built-in collections
• Type aliases
• int/float
• NoReturn (not strictly necessary, but a fairly easy topic)
• Installing third-party stubs

Advanced Topics

The are fairly complicated topics, but basically required when typing a non-trivial code base:

• Callable
• Writing generics
• Protocols
• type[...]
• typing.TYPE_CHECKING and circular imports
• TypeVar and AnyStr
• overloads
• Literal

What not to include

• # type annotations (except # type: ignore)

The following topics could arguably be included, but for simplicity's sake, I'd suggest to skip them in this basic tutorial:

• NewType
• ClassVar
• Final
• Annotated
• NamedTuple
• TypedDict

Other Thoughts

• We can use a newer version of Python (e.g. 3.8+) for simplicity and add a note that not all features are available in older Python versions.
• We should probably just use from __future__ import annotations and skip the whole forward references/quoting types problem.

No tutorial file, entry point, or test is named in the issue. Start by locating the existing tutorial documentation and compare it with the proposed basic and advanced topic lists. Done means agreeing on the tutorial scope, Python version guidance, included typing topics, and exclusions, then documenting those decisions.