Prerequisites: Object-Oriented Programming in Python, Object-Oriented Programming in Python 

Constructors are generally used for instantiating an object. The task of constructors is to initialize(assign values) to the data members of the class when an object of the class is created. In Python the __init__() method is called the constructor and is always called when an object is created.

In object-oriented programming (OOP), a constructor is a special method that is used to initialize the properties of an object when it is created. In Python, constructors are defined using the init() method, which is called automatically when a new instance of a class is created.

The constructor allows you to set the initial state of an object by passing in values for its properties. For example, if you have a class called Car, you can define a constructor to set the initial values of the car's properties such as its make, model, and year.

Here's an example of a basic Car class with a constructor: 

class Car:
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year

In this example, the constructor takes three parameters (make, model, and year) and initializes the corresponding properties of the Car object.

When you create a new instance of the Car class, you pass in values for these parameters to set the initial state of the object: 

my_car = Car("Toyota", "Corolla", 2022)

Now, the my_car object has its make property set to "Toyota", its model property set to "Corolla", and its year property set to 2022.

Constructors are an important part of OOP and allow you to create objects with the correct initial state. They also allow you to enforce rules for how objects can be created and initialized, which can help prevent errors and make your code more reliable.