# missing-type-function-argument (ANN001) Derived from the **flake8-annotations** linter. ## What it does Checks that function arguments have type annotations. ## Why is this bad? Type annotations are a good way to document the types of function arguments. They also help catch bugs, when used alongside a type checker, by ensuring that the types of any provided arguments match expectation. ## Example ```python def foo(x): ... ``` Use instead: ```python def foo(x: int): ... ```