[Hasnep]

I've had lots of success using pyright [1] for Python projects, it has sensible defaults and can be configured with a pyproject.toml file so everyone's using the same settings. I use the Pylance VSCode extension to catch errors earlier, but I also put it in pre-commit and as a CI check, so all contributors are committing the same quality of typed code.

With more complex types, I've found it isn't necessary to do anything more complex than specifying the element type of a list or dict most of the time. I have typehinted lambda function arguments before, but just using the plain Callable typehint is usually enough. When I forget if I need to use an Iterator or an Iterable (which is every time), then I just try one and run the type checker and change it to the other if i guessed incorrectly.

Type checking Python can become complex if you expect to be able to express everything in the typehints, but Python's type system isn't powerful enough for that. I feel its strength is that it lets you add as much detail to the types as is convenient.

[1] https://github.com/microsoft/pyright