Static Type Check For Abstract Method In Python

How do I make sure that a method implementing an abstract method adheres to the python static type checks. Is there a way in pycharm to get an error if the return type is incorrect

Solution 1:

No there's not a (simple) way to enforce this.

And actually there isn't anything wrong with your Chihuahua as Python's duck typing allows you to override the signature (both arguments and types) of bark. So Chihuahua.bark returning an int is completely valid code (although not necessarily good practice as it violates the LSP). Using the abc module doesn't change this at all as it doesn't enforce method signatures.

To "enforce" the type simply carry across the type hint to the new method, which makes it explicit. It also results in PyCharm showing a warning.

import abc

classDog:@abc.abstractmethod
    defbark(self) -> str:
        raise NotImplementedError("A dog must bark")

classChihuahua(Dog):defbark(self) -> str:# PyCharm warns against the return typereturn123