有没有Python函数可以在标记化后用特定的字符标记句子的开头和结尾？

import nltk

text = "This is the first sentence. This is the second sentence. And this is the third sentence."

# 使用nltk.sent_tokenize()函数将文本分割成句子
sentences = nltk.sent_tokenize(text)

# 在每个句子的开头和结尾添加特定的标记字符
marked_sentences = ['<s> ' + sentence + ' </s>' for sentence in sentences]

# 打印标记化后的句子
for sentence in marked_sentences:
    print(sentence)

<s> This is the first sentence. </s>
<s> This is the second sentence. </s>
<s> And this is the third sentence. </s>