**Abstract Method** is a method that should be redefined in subclasses.

To create an abstract method, you should import the `@abstractmethod` decorator from the `abc` library.
```python
from abc import ABC, abstractmethod
```
> Note
>
> Pay attention: decorator is imported without the `@` symbol.

from abc import ABC, abstractmethod

class SomeClass(ABC):
    @abstractmethod
    def some_method():
        pass

instance = SomeClass()  # TypeError

The abstract methods should be implemented in subclasses. You can't create a subclass without redefining all abstract methods:

from abc import ABC, abstractmethod

class AbstractParent(ABC):
    @abstractmethod
    def first_method():
        pass
    
    @abstractmethod
    def second_method():
        pass

class Child(AbstractParent):
    def first_method(self):
        print("The first method")

instance = Child()  # TypeError

The class `Child` saved the **Abstract Class** state because the `second_method` is not redefined, and the `ABC` class exists in the inheritance hierarchy.

from abc import ABC, abstractmethod

class AbstractParent(ABC):
    @abstractmethod
    def first_method():
        pass
    
    @abstractmethod
    def second_method():
        pass

class Child(AbstractParent):
    def first_method(self):
      print("The first method")

    def second_method(self):
        print("The second method")


instance = Child()
instance.first_method()
instance.second_method()

> Note
>
> The abstract classes and methods exist to provide a strict class structure.

This course covers Object-Oriented Programming (OOP) in Python, starting with the basics and progressing to advanced concepts. You will implement a User model to gain practical experience and understanding of OOP features. By the end of the course, you will have a strong foundation in OOP and a deeper knowledge of Python's inner workings.

Let's start! The Object-Oriented Programming basic concepts are waiting for you here! In this section, you will get acquainted with the most important concepts for understanding Object-Oriented Programming.

Inheritance - the first of the OOP principles. The entities can be inherited from other ones. You learn how it works in code here.

Inheritance - the second of the OOP principles. The attributes and methods can be closed inside the class and used by the class only. Here you learn how to code with different access modifiers.

Polymorphism and abstraction are the third and fourth of the OOP principles. These principles are not easy to understand. Here you will get to know them in the simplest ways.

The magic methods make sandbox from Python. It's a unique Python tool you can't see in other languages. Here you learn how to use these methods and about the flexibility that they bring to Python.

In-Depth Python OOP

Abstract Method