例如：
class Pizza:
def __init__(self, toppings):
self.toppings = toppings
@staticmethod
def validate_topping(topping):
if topping == "pineapple":
raise ValueError("No pineapples!")
else:
return True
ingredients = ["cheese", "onions", "spam"]
if all(Pizza.validate_topping(i) for i in ingredients):
pizza = Pizza(ingredients)