class Counter:
def __init__(self):
self.count = 0
def inc_by(self, value):
self.count += value
def inc_by_amount(self, value, amount):
self.count += value * amount
counter = Counter()
# No return: the call gives None
result = counter.inc_by(1)
# counter.count is 1
print(f"{result = }")
print(f"{counter.count = }")
counter.inc_by_amount(2, 5)
# counter.count is 11
print(f"{counter.count = }")