docstr: There are two unique lengths in the toy dataset
docstr_tok: ["There","are","two","unique","lengths","in","the","toy","dataset"]
code: def test_sort_by_length(self, train_file):
      """
      There are two unique lengths in the toy dataset
      """
      train_set = data.read_dataset(str(train_file), WVType.OTHER, 1)
      sorted_dataset = data.sort_dataset_by_len(train_set)
      assert list(sorted_dataset.keys()) == [4, 5]
      assert len(sorted_dataset[4]) == len(train_set) // 3
      assert len(sorted_dataset[5]) == 2 * len(train_set) // 3
  
file_path: stanza/stanza/tests/classifiers/test_data.py
imports: import json
  import pytest
  import stanza.models.classifiers.data
  from stanza.models.classifiers.utils import WVType
  from stanza.models.common.vocab import PAD, UNK
  from stanza.models.constituency.parse_tree import Tree
label_desc: Use image node_id 5 for calling the TestClassifierData obj's underlying member method code with example usage: obj.test_sort_by_length(train_file) without return types