What is the __add__ method?

The __add__ method in Python is a special method (also known as a magic method) that allows you to define the behavior of the addition operator (+) for instances of a class. When you use the + operator between two objects of a class that implements the __add__ method, Python calls this method to perform the addition.

Syntax

The __add__ method typically has the following signature:

def __add__(self, other):
    # Implementation

• self: The first operand (the instance of the class).
• other: The second operand (the object being added).

Example

Here's an example of a simple class that implements the __add__ method to concatenate two lists:

class MagicList:
    def __init__(self, items):
        self.items = items

    def __add__(self, other):
        if isinstance(other, MagicList):
            return MagicList(self.items + other.items)
        return NotImplemented

# Usage
list1 = MagicList([1, 2, 3])
list2 = MagicList([4, 5, 6])
result = list1 + list2

print(result.items)  # Output: [1, 2, 3, 4, 5, 6]

In this example, when list1 + list2 is executed, the __add__ method is called, which concatenates the items of both MagicList instances and returns a new MagicList instance containing the combined items.