I want to add/append a word after verb "VRB" - How do I do it?

This is the Code and what I want to achieve is that I want to append a word after Noun/verb. The output I am trying is somewhat like Lopa is not a beautiful girl:

    sentence = 'Lopa is a beautiful girl'

    pos_tagged = nltk.pos_tag(nltk.word_tokenize(sentence))
    print(pos_tagged)

    Output: [('Lopa', 'NNP'), ('is', 'VBZ'), ('a', 'DT'), ('beautiful', 'JJ'), ('girl', 'NN')]

    Outpust will be like: Lopa is not Beautiful

Any links, any source, any help. Thanks in Advance...