Demonstrating the successor function

quackquack.py

class Duck:
    def __init__(self, quacks=0):
        self._quacks = quacks

    def __add__(self, more_quacks):
        return Duck(self._quacks + more_quacks)

    def __str__(self):
        return ('quack ' * self._quacks)[:-1]

succ = lambda i: i + 1

print(f'Your Int -> Int function: succ(1) == {succ(1)}')
print(f'My   Int -> Int function: succ(Duck(1)) == {succ(Duck(1))}')