[code-quality] __all__ defined inside a class

Hi folks, I've just noticed that a legacy piece of code I'm working with contains the following pattern:

class SomeClass(object): __all__ = ['add', 'delete']

def __init__(self): pass

def get(self): pass

def add(self, x): pass

def delete(self, x): pass

And the caller of this class actually uses the .get() method. I have this in at least 10 different places.

I wasn't able to find any information about __all__ having any special meaning when defined inside a class so this looks like a mistake.

Q1: Do we want pylint to warn about __all__ being detected not at module level ?

Q2: Do we want another check to warn about class attributes staring with single/double underscore ?

-- Alex