PYTHON

__add__

"""
Magic method __add__ is called when a "+" is used on any object. 
Given example shows what I mean: print(some_object + other_object)
This may give error often, so that means given objects don't have __add__ method
"""

class Test:
    def __init__(self, x):
        self.x = x
    
    def __add__(self, other):
    	""" 
    	self represents the object that is first and other is object after
    	"+" sign. What I say here is that I expect to have attribute "x" 
    	in both objects and I will try to add them together. This SHOULD BE
    	used for objects of the same type.
    	"""
    	return self.x + other.x

t = Test(5)
t2 = Test(2)	# Now I can add these two objects together.
print(t + t2)	# 7, without __add__ the object doesn't understand the "+" sign.