class Tall:
    def __init__(self, tall):
        self.tall = tall

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

a = Tall(4)
b = Tall(5)
c = Tall(4)
d = a

print(a == b) # False : 4!=5
print(a == c) # True: 4 == 4
print(a == d) # True: a == d

print(a is b) # False : a != b
print(a is c) # False: a != c
print(a is d) # True: a == d