How to create object of derived class inside base class in Python?

Question

I have a code like this:

class Base:
    def __init__(self):
        pass

    def new_obj(self):
        return Base()  # ← return Derived()

class Derived(Base):
    def __init__(self):
        pass

In the line with a comment I actually want not exactly the Derived object, but any object of class that self really is.

Here is a real-life example from Mercurial.

How to do that?

Answer 1

def new_obj(self):
    return self.__class__()