__init__ is the constructor method in Python classes.

It runs automatically when an object is created.

Its main purpose is to initialize instance variables.

class Student:
    def __init__(self, name, rollno, marks):
        self.name = name
        self.rollno = rollno
        self.marks = marks

• self must be the first parameter
• The method name must be __init__
• It is optional, but very commonly used