I’m trying to create a Python class (let’s say ETL) which obtains it’s behaviour from a number of base classes (Extractor, Transformer, Loader). However, for one of these base classes the behaviour should be determined based on the parameters passed during the intialization of ETL.

I have tried adding the specific transformer class to self.__class__bases__ in Transformer.__init__ but that seems to create all kinds of issues including TypeError: Cannot create a consistent method resolution order (MRO).

How can I best architect this?

class Extractor:
    def extract(self):
        pass


class FooTransformer:
    def transform(self):
        pass


class BarTransformer:
    def transform(self):
        pass


class Transformer:
    def __init__(self):
        # dynamically decide which transformer to inherit based on self.transformation?
        pass


class Loader:
    def load(self):
        pass


class ETL(Extractor, Transformer, Loader):
    def __init__(self, transformation):
        self.transformation = transformation

    def run(self):
        self.extract()
        self.transform()
        self.load()


etl = ETL()
etl.run()