✅ 1. Using Abstract Base Classes
from abc import ABC, abstractmethod
# Creating an abstract base class
class Animal(ABC):
    
    @abstractmethod
    def sound(self):
        # Abstract method with no body
        pass
    def breathe(self):
        # Concrete method
        print("Breathing...")
# Subclass inheriting from Animal
class Dog(Animal):
    
    def sound(self):
        # Overriding abstract method
        print("Bark")
class Cat(Animal):
    
    def sound(self):
        # Overriding abstract method
        print("Meow")
# Creating instances
d = Dog()
c = Cat()
d.sound()     # Output: Bark
c.sound()     # Output: Meow
d.breathe()   # Output: Breathing...
✅ 2. Trying to instantiate an abstract class (throws error)
a = Animal()  # ❌ Error: Can't instantiate abstract class
✅ 3. Abstraction with Partial Implementation
from abc import ABC, abstractmethod
class Vehicle(ABC):
    @abstractmethod
    def start(self):
        pass
    @abstractmethod
    def stop(self):
        pass
class Car(Vehicle):
    
    def start(self):
        print("Car started")
    def stop(self):
        print("Car stopped")
c = Car()
c.start()     # Output: Car started
c.stop()      # Output: Car stopped