请您帮助我将以下Python函数转换为更加简洁和易懂的版本：
```python
def calculate_age(birth_year):
    from datetime import datetime
    now = datetime.now()
    age = now.year - birth_year
    return age
```
要求：缩短代码行数，使其更简洁。
user
```python
def calculate_age(birth_year):
    return datetime.now().year - birth_year
```
assistant