Simple calculation using datetime

[mapypy]

Hi, How can i calculate age using date time without hardcoding current year? The way I want to solve and validate is as follows:

from datetime import date

def get_age(birth_year):
    """
    returns the age based on current year
    """
    current_year = date.today().year
    
    return 

validate age:

assertion('12a', get_age(1950), 71)
assertion('12b', get_age(1990), 31)
assertion('12c', get_age(2020), 1)