def get_last_tid(self):
        try:
            spec = {'tid': {'$gt': 0}}
            sort = [('tid', -1)]
            row = self.db.docs.find_one(spec, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return row['tid']
        return 0
def residual_with_slice_fn(inp, out):
      inp_sliced = array_ops.slice(inp, [0, 0], [-1, 3])
      return inp_sliced + out