code: def test_define_buckets(max_seq_len, step, expected_buckets):
      buckets = data_io.define_buckets(max_seq_len, step=step)
      assert buckets == expected_buckets
  
imports: import os
  import random
  from tempfile import TemporaryDirectory
  from typing import Optional, List, Tuple
  import numpy
  import pytest
  import torch
  from sockeye import constants
  from sockeye import data_io
  from sockeye import utils
  from sockeye import vocab
  from sockeye.test_utils import tmp_digits_dataset
  from sockeye.utils import SockeyeError, get_tokens, seed_rngs
label_desc: Use image node_id 1 for calling a global function with example usage: test_define_buckets(max_seq_len, step, expected_buckets) without return types