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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def tokenize_text(string):
 """ Tokenize input text to paragraphs, sentences and words. Tokenization to paragraphs is done using simple Newline algorithm For sentences and words tokenizers above are used :param string: Text to tokenize :type string: str or unicode :return: text, tokenized into paragraphs, sentences and words :rtype: list of list of list of words """

    string = six.text_type(string)
    rez = []
    for part in string.split('\n'):
        par = []
        for sent in tokenize_sents(part):
            par.append(tokenize_words(sent))
        if par:
            rez.append(par)
    return rez