Fix generator types and check with mypy

[mehaase]

The command methods are generators but the type information currently doesn't reflect that. These should have a type like -> typing.Generator[dict,$type,None]. Check that all generated types are correct by running mypy on the entire module.

[mehaase]

This is fixed in a series of commits: d318f7f, 3750403, 184ffb7, a45fca3, 2f82250, 7ca62f9, and cd93d05. The code is regenerated at 1bb0735.