'Return a list of noun phrases (strings) for body of text.'

def extract(self, text):

    sentences = nltk.tokenize.sent_tokenize(text)
    noun_phrases = []
    for sentence in sentences:
        parsed = self._parse_sentence(sentence)
        phrases = [_normalize_tags(filter_insignificant(each, self.INSIGNIFICANT_SUFFIXES)) for each in parsed if (isinstance(each, nltk.tree.Tree) and (each.label() == u'NP') and (len(filter_insignificant(each)) >= 1) and _is_match(each, cfg=self.CFG))]
        nps = [tree2str(phrase) for phrase in phrases]
        noun_phrases.extend(nps)
    return noun_phrases
