':return: the given file(s) as a list of sentences. Each sentence
is represented as a list of tagged chunks (in tree form).
:rtype: list(list(Tree))
:param tag: `\'pos\'` (part of speech), `\'sem\'` (semantic), or `\'both\'`
to indicate the kind of tags to include.  Semantic tags consist of
WordNet lemma IDs, plus an `\'NE\'` node if the chunk is a named entity
without a specific entry in WordNet.  (Named entities of type \'other\'
have no lemma.  Other chunks not in WordNet have no semantic tag.
Punctuation tokens have `None` for their part of speech tag.)'

def tagged_sents(self, fileids=None, tag=(u'pos' or u'sem' or u'both')):

    return self._items(fileids, u'chunk', True, (tag != u'sem'), (tag != u'pos'))
