What is the purpose of base classes in Python if you're already referring to the implementation classes consistently
Base classes in Python serve to share implementation details and document likenesses. We don't need to use a common base class for things that function similarly though, as we use protocols and duck typing. For these validation functions, we might not have a use for a class at all; Java is designed to force people to put everything inside classes, but if all you have in your class is one static method, the class is just noise. Having a common superclass would enable you to check dynamically for that using isinstance, but then I'd really wonder why you're handling them in a context where you don't know what they are. For a programmer, the common word in the function name is probably enough.
I have a bunch of python classes that are responsible for validating files like so:

java file validator
html file validator
css file validator
javascript file validator

All of these classes define a validate_file(path) and validate_string(string) function.
In the client code of my application, I store all of these validators in an array and I iterate through all of them and call the methods on them in exactly the same way.
Is there a purpose in my case of defining a base "validator" class which defines these methods as abstract? How can I benefit from making these individual classes adhere to the base class? Or maybe in other words, what features would be unlocked if I had a base class with all of these validators implementing it?