I don't exactly know what Pycharm does but I only add type hints when Pycharm's default type checker raises a complaint or is unable to infer the type. To me th

I don't exactly know what Pycharm does but I only add type hints when Pycharm's default type checker raises a complaint or is unable to infer the type. To me that's just the perfect middle ground. Sometimes adding a type to a single object (e.g. `df: pd.DataFrame = ...`) only once at the top of a 20-50 line function, is usually sufficient for Pycharm to infer all other types downstream without ambiguity.