'Compute the overlap between text and hypothesis.
:param toktype: distinguish Named Entities from ordinary words
:type toktype: \'ne\' or \'word\''

def overlap(self, toktype, debug=False):

    ne_overlap = set((token for token in self._overlap if ne(token)))
    if (toktype == 'ne'):
        if debug:
            print('ne    overlap', ne_overlap)
        return ne_overlap
    elif (toktype == 'word'):
        if debug:
            print('word    overlap', (self._overlap - ne_overlap))
        return (self._overlap - ne_overlap)
    else:
        raise ValueError(("Type    not    recognized:'%s'" % toktype))
