'Performs a token-based classification (section 4) over the given
tokens, making use of the orthographic heuristic (4.1.1), collocation
heuristic (4.1.2) and frequent sentence starter heuristic (4.1.3).'

def _annotate_second_pass(self, tokens):

    for (t1, t2) in _pair_iter(tokens):
        self._second_pass_annotation(t1, t2)
        (yield t1)
