message: Fix docstring for flush() method
diff: @@ -187,7 +187,7 @@ class QuantileAccumulator(saver.BaseSaverBuilder.SaveableObject):
  stamp_token: Expected current token.
  next_stamp_token: Next value for the token.
  Returns:
  - A list of quantiles or approximate boundaries.
  + The flush operation.
  """
  return gen_quantile_ops.quantile_accumulator_flush(
  quantile_accumulator_handle=self._quantile_accumulator_handle,
  