如何查找字典中不存在的key？

my_dict = {"name": "John", "age": 25, "city": "New York"}

# 使用get()方法查找存在的key
name = my_dict.get("name")
print(name)  # 输出：John

# 使用get()方法查找不存在的key
country = my_dict.get("country", "Unknown")
print(country)  # 输出：Unknown

my_dict = {"name": "John", "age": 25, "city": "New York"}

# 使用in关键字判断key是否存在
if "country" in my_dict:
    country = my_dict["country"]
    print(country)
else:
    print("Key 'country' does not exist in the dictionary.")