An implementation of an Abstract Base Class in python

CustomABS.py

def makeFun(name, *args):
        exec("""def {}({}): raise NotImplementedError("'{}' is not implemented!")""".format(name, ', '.join(args), name))
        return locals()[name]

class ABC(type):
    def __init__(cls, name, bases, dct):
        for k, v in cls.__dict__.items():
            if not k.startswith("__") and callable(v):
                setattr(cls, k, makeFun(k, *v.__code__.co_varnames))
        
class Class(metaclass=ABC):
    def __init__(self, **kwargs):
        pass
    
    def shouldFail(self, a, b):
        pass
    
a = Class()
try:
    a.shouldFail(1, 2)
except NotImplementedError as e:
    print(str(e))