6.3. Inheritance Override

Child inherits all fields and methods from parent
Used to avoid code duplication

override: When child has method or attribute with the same name as parent. In such case child attribute will be used (will overload parent).

6.3.1. Override Method

Child class will override parent's method

>>> class User:
...     def login(self):
...         print('User login')
>>>
>>> class Admin(User):
...     def login(self):
...         print('Admin login')

Calling this method will use the child's method:

>>> mark = Admin()
>>> mark.login()
Admin login

6.3.2. Override Init

__init__() is inherited as any other method
Child class will override parent's __init__() method
Warning: Call to __init__ of super class is missed

>>> class User:
...     def __init__(self):
...         print('User init')
>>>
>>> class Admin(User):
...     def __init__(self):
...         print('Admin init')

Calling this method will use the child's method:

>>> mark = Admin()
Admin init

6.3.3. Override Class Variables

Class variables are inherited as any other attribute
Child class will override parent's class variable

>>> class User:
...     ROLE = 'user'
>>>
>>> class Admin(User):
...     ROLE = 'admin'

Using this class variable will use the child's field:

>>> mark = Admin()
>>> mark.ROLE
'admin'

6.3.4. Override Instance Variables

Instance variables are inherited as any other attribute
Child __init__() method will override the parent's __init__() method
Child class will override parent's instance variable

>>> class User:
...     def __init__(self):
...         self.role = 'user'
>>>
>>> class Admin(User):
...     def __init__(self):
...         self.role = 'admin'
>>>
>>>
>>> mark = Admin()
>>> mark.role
'admin'

6.3.5. Assignments