def lemmatize(self, text):
<EOL>if text.strip() == "<STR_LIT>":<EOL><INDENT>return []<EOL><DEDENT>parsed_sentences = self._parse_text(text)<EOL>_lemmalist = []<EOL>for s in parsed_sentences:<EOL><INDENT>tokens = s.split()<EOL>for i, t in enumerate(tokens):<EOL><INDENT>if t.startswith('<STR_LIT:/>'):<EOL><INDENT>continue<EOL><DEDENT>w, tag, phrase, role, lemma = t.split('<STR_LIT:/>')<EOL>lemma = lemma.replace(u"<STR_LIT>", "<STR_LIT>")<EOL>lemma = lemma.strip().replace("<STR_LIT>", "<STR_LIT:/>")<EOL>if w[<NUM_LIT:0>].isupper() and i > <NUM_LIT:0>:<EOL><INDENT>lemma = lemma.title()<EOL><DEDENT>elif tag.startswith("<STR_LIT:N>") and i == <NUM_LIT:0>:<EOL><INDENT>lemma = lemma.title()<EOL><DEDENT>if w in string.punctuation or lemma == '<STR_LIT:/>':<EOL><INDENT>continue<EOL><DEDENT>else:<EOL><INDENT>lemma = lemma<EOL><DEDENT>_lemmalist.append((lemma, tag))<EOL><DEDENT><DEDENT>return _lemmalist<EOL>
Return a list of (lemma, tag) tuples.

        :param str text: A string.