How to inherit from a base class, when the inheriting class requires the inherited class in Python?

Question

Given the following requirements:

1. We have the classes Foundation and Data
2. Data is a child class of Foundation
3. Instances of Foundation hold an instance of Data

Python code:

from __future__ import annotations

class Foundation():
    data: Data

    def __init__(self):
        self.data = Data()

class Data(Foundation):
    pass

Foundation()

However, the given script exits with an RecursionError . Why and how can I implement the three given requirements?

Answer 1

You can use super to avoid calling an object that calls an object that calls an object... and so on untill recursion error.

from __future__ import annotations

class Foundation():
    def __init__(self, data):
        self.data = data
        print(self.data)

class Data(Foundation):
    def __init__(self):
        super(Data, self).__init__(self)

Data()

Now you called Data , and data's super is a Foundation , which holds a reference to it's child.

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