如何切换字符串中单词的位置？

def reverse_words(string):
    # 将字符串按照空格分割成单词数组
    words = string.split(" ")
    
    # 反转单词数组
    words.reverse()
    
    # 将反转后的单词数组重新连接成字符串
    reversed_string = " ".join(words)
    
    return reversed_string

string = "Hello World! This is a test."
reversed_string = reverse_words(string)
print(reversed_string)

test. a is This World! Hello