Chunk named entities.

def tag(tagger, args):
  """Chunk named entities."""
  for l in args.input:
    words = l.strip().split()
    line_annotations = [u"{:<16}{:<5}".format(w,p) for w, p in tagger.annotate(words)]
    _print(u"\n".join(line_annotations))
    _print(u"")