回傳值

def square(x):
    return x ** 2

result = square(5)  # 25

def divide(a, b):
    quotient = a // b
    remainder = a % b
    return quotient, remainder  # 回傳 tuple

q, r = divide(17, 5)
print(f"商：{q}, 餘：{r}")  # 商：3, 餘：2

def find_first_even(numbers):
    for num in numbers:
        if num % 2 == 0:
            return num  # 找到就返回
    return None  # 找不到返回 None

def greet():
    print("Hello")
    # 沒有 return，隱式返回 None

result = greet()
print(result)  # None