The total_ordering() function in the functools module is a decorator that is used to simplify the implementation of classes that need to support rich comparison operations (i.e., __lt__ , __gt__ , __le__ , __ge__, __eq__, __ne__ ). The six comparison methods are used for implementing the internal workings of the comparison operators as shown below.

method operator name
__lt__ < less than
__gt__ > greater than
__le__ <= less than or equal to
__ge__ >= greater then or equal to
__eq__ == equal
__ne__ != not equal

How the total_ordering decorator works

The @total_ordering() function performs a number of checks to make sure that implementations are consistent and correct. The only conditions is that the target class should:

  • define __eq__() method.
  • define any one of __lt__(), __le__(), __gt__(), or __ge__() methods. 

When the two conditions are met, the function automatically fills in the missing methods.

class class_to_decorate
    def __eq__(self, other):
    def __gt__(self, other):
from functools import total_ordering 

class Person: 
    def __init__(self, name, age): = name 
        self.age = age 

    def __eq__(self, other): 
        return (, self.age) == (, other.age) 

    def __lt__(self, other): 
        return self.age < other.age 

p1 = Person('John', 20) 
p2 = Person('Mike', 30) 

print(p1 < p2) 
print(p1 > p2) 
print(p1 <= p2)
print(p1 >= p2)
print(p1 == p2)
print(p1 != p2)