'Return a list of word tokens.
:param text: string of text.
:param include_punc: (optional) whether to include punctuation as separate tokens. Default to True.'

def tokenize(self, text, include_punc=True):

    tokens = nltk.tokenize.word_tokenize(text)
    if include_punc:
        return tokens
    else:
        return [(word if word.startswith("'") else strip_punc(word, all=False)) for word in tokens if strip_punc(word, all=False)]
