How to call multiple base classes __init__ in python

Question

I have doubt if multiple classes inherited to a derived class. How can we call the init of all base classes.

class Base1(object):
    def __init__(self):
        print('Constructor of Base1 Class')

class Base2(object):
    def __init__(self):
        print('Constructor of Base2 Class')

class Base3(object):
    def __init__(self):
        print('Constructor of Base3 Class')

class Derived(Base1, Base2, Base3):
    def __init__(self):
        super(Derived, self).__init__()
        print('Constructor of Derived Class')

if __name__ == '__main__':
   inst = Derived()

When i run the above code. I get the output as below

Constructor of Base1 Class
Constructor of Derived Class

I think Base2 and Base3 __init__ are not getting called. Is there a way to do it

Answer 1

You need to call super() in each constructor so that it calls __init__() from list of _mro_

class Base1(object):
    def __init__(self):
        super().__init__()
        print('Constructor of Base1 Class')

class Base2(object):
    def __init__(self):
        super().__init__()
        print('Constructor of Base2 Class')

class Base3(object):
    def __init__(self):
        super().__init__()
        print('Constructor of Base3 Class')

class Derived(Base1, Base2, Base3):
    def __init__(self):
        #  super(Derived, self).__init__()
        super().__init__()
        print('Constructor of Derived Class')

if __name__ == '__main__':
   inst = Derived()


Constructor of Base3 Class
Constructor of Base2 Class
Constructor of Base1 Class
Constructor of Derived Class

Answer 2

I think it is a proper way to do it:

class Base1(object):
    def __init__(self):
        print('Constructor of Base1 Class')

class Base2(object):
    def __init__(self):
        print('Constructor of Base2 Class')

class Base3(object):
    def __init__(self):
        print('Constructor of Base3 Class')

class Derived(Base1, Base2, Base3):
    def __init__(self):
        Base1.__init__(self)
        Base2.__init__(self)
        Base3.__init__(self)
        print('Constructor of Derived Class')

Output:

inst = Derived()
Constructor of Base1 Class
Constructor of Base2 Class
Constructor of Base3 Class
Constructor of Derived Class

Source: https://www.journaldev.com/14623/python-multiple-inheritance