from datetime import date


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

    @classmethod
    def from_birth_year(cls, name, birth_year):
    	# Since `cls` refers to the class itself (`Person`), calling this
        #	`classmethod` creates an instance of `Person`.
    	return cls(name, date.today().year - birth_year)

    def display(self):
    	print(f"{self.name}'s age is: {self.age}")


bob = Person("Bob", 25)
bob.display()  # Bob's age is: 25

alice = Person.from_birth_year("Alice", 1985)
alice.display()  # Alice's age is: 39