我在Python中使用自定义函数时遇到了麻烦

def my_function():
    print("Hello, World!")

my_function()  # 确保函数定义在调用之前

def add(a, b):
    if not isinstance(a, (int, float)) or not isinstance(b, (int, float)):
        raise TypeError("Both arguments must be numbers")
    return a + b

print(add(1, 2))  # 正确调用
print(add(1, "2"))  # 会引发TypeError

global_var = 10

def modify_global():
    global global_var  # 声明使用全局变量
    global_var += 1

modify_global()
print(global_var)  # 输出11

def calculate_square(x):
    return x * x  # 确保函数有返回值

result = calculate_square(5)
print(result)  # 输出25

# 使用lambda函数计算两个数的和
add = lambda x, y: x + y
print(add(3, 4))  # 输出7

def greet(name):
    return f"Hello, {name}!"

def calculate_average(numbers):
    if not numbers:
        return 0
    return sum(numbers) / len(numbers)

# 调用函数
print(greet("Alice"))  # 输出: Hello, Alice!
print(calculate_average([1, 2, 3, 4, 5]))  # 输出: 3.0