如何追加到函数中的嵌套字典

nested_dict = {}

def append_to_nested_dict(key, value):
    # 在函数中引用全局变量nested_dict
    global nested_dict
    # 将键和值添加到嵌套字典中
    nested_dict[key] = value

append_to_nested_dict('key1', 'value1')
append_to_nested_dict('key2', 'value2')

append_to_nested_dict('key3', 'value3')
append_to_nested_dict('key4', 'value4')

print(nested_dict)

nested_dict = {}

def append_to_nested_dict(key, value):
    global nested_dict
    nested_dict[key] = value

append_to_nested_dict('key1', 'value1')
append_to_nested_dict('key2', 'value2')
append_to_nested_dict('key3', 'value3')
append_to_nested_dict('key4', 'value4')

print(nested_dict)