missing-return-type-class-method (ANN206)

Derived from the flake8-annotations linter.

Fix is sometimes available.

What it does

Checks that class methods have return type annotations.

Why is this bad?

Type annotations are a good way to document the return types of functions. They also help catch bugs, when used alongside a type checker, by ensuring that the types of any returned values, and the types expected by callers, match expectation.

Example

class Foo:
    @classmethod
    def bar(cls):
        return 1

Use instead:

class Foo:
    @classmethod
    def bar(cls) -> int:
        return 1