CODEWITHSUNDEEP
pythonpython-3.xinheritancesupermagic-methods
Thinh Le
Thinh Le

Reputation: 662

Method with same name in Derived class wrongly called in Parent class while using inheritance in Python

I have the following code

class Parent(bytes):
    def __init__(self, validate=True):
        super().__init__()
        if validate:
            self.validate()

    def validate(self):
        print("Validation of Parent")
        return self

class Derived(Parent):
    def __init__(self, validate=True):
        super().__init__()
        if validate:
            self.validate()

    def validate(self):
        print("Validation of Derived")
        return self

object = Derived()

It is also required that init() has to be called in Derived to unpack different types of data. Also validate=True has to be passed into init() as argument and this part has to stay to avoid flake8 & pylint warning check:

if validate:
    self.validate()

And my current output is:

Validation of Derived
Validation of Derived

But I want expected output to be:

Validation of Parent
Validation of Derived

Is there a way to modify how the validate() method is called in Parent class to avoid this error?

Upvotes: 1

Views: 186

Answers (1)

quamrana
quamrana

Reputation: 39414

Since the Parent class __init__() already calls validate() your derived class need not. But, your version of validate should:

class Parent(bytes):
    def __init__(self, validate=True):
        super().__init__()
        if validate:
            self.validate()

    def validate(self):
        print("Validation of Parent")
        return self

class Derived(Parent):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # do specialised setup here.

    def validate(self):
        super().validate()
        print("Validation of Derived")
        return self

object = Derived()

Output as expected.

Update: Just be aware that I've shown the call to super().__init__() first, which, of course calls down to your validate(). You may actually need to perform the specialised setup first and then do the super call to init.

Upvotes: 2

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