code: def test_ngram_basic_longer_no_overlap(
      synthetic_dataset, reader_factory
  ):
      """Tests basic ngram with no delta threshold with no overlaps of timestamps."""
      fields = {
          -5: [TestSchema.id, TestSchema.id2, TestSchema.matrix],
          -4: [TestSchema.id, TestSchema.id2, TestSchema.image_png],
          -3: [TestSchema.id, TestSchema.id2, TestSchema.decimal],
          -2: [TestSchema.id, TestSchema.id2, TestSchema.sensor_name],
          -1: [TestSchema.id, TestSchema.id2],
      }
  
      dataset_dicts = synthetic_dataset.data
      ngram = NGram(
          fields=fields,
          delta_threshold=10,
          timestamp_field=TestSchema.id,
          timestamp_overlap=False,
      )
      with reader_factory(
          synthetic_dataset.url,
          schema_fields=ngram,
          shuffle_row_groups=False,
      ) as reader:
          timestamps_seen = set()
          for actual in reader:
              expected_ngram = _get_named_tuple_from_ngram(
                  ngram, dataset_dicts, actual[min(actual.keys())].id
              )
              np.testing.assert_equal(actual, expected_ngram)
              for step in actual.values():
                  timestamp = step.id
                  assert timestamp not in timestamps_seen
                  timestamps_seen.add(timestamp)
  
imports: from decimal import Decimal
  import numpy
  import pytest
  import tensorflow.compat.v1
  from unittest import mock
  from petastorm import make_reader
  from petastorm.ngram import NGram
  from petastorm.tests.conftest import SyntheticDataset, maybe_cached_dataset
  from petastorm.tests.test_common import create_test_dataset, TestSchema
  from petastorm.tests.test_tf_utils import create_tf_graph
  from petastorm.tf_utils import tf_tensors
label_desc: Use image node_id 18 for calling a global function with example usage: test_ngram_basic_longer_no_overlap(synthetic_dataset, reader_factory) without return types