如何将日期的原始字符串转换为年龄？

from datetime import datetime

def calculate_age(date_str):
    current_timestamp = datetime.now().timestamp()
    date_obj = datetime.strptime(date_str, "%Y-%m-%d")
    date_timestamp = date_obj.timestamp()
    age_in_seconds = current_timestamp - date_timestamp
    age_in_years = age_in_seconds / (365.25 * 24 * 60 * 60)  # 平均年长365.25天
    return int(age_in_years)

date_string = "1990-01-01"
age = calculate_age(date_string)
print("年龄：", age)