code: def test_specify_columns_to_read(scalar_dataset, reader_factory):
      """Just a bunch of read and compares of all values to the expected values using the different reader pools"""
      with reader_factory(
          scalar_dataset.url, schema_fields=["id", "float.*$"]
      ) as reader:
          sample = next(reader)
          assert set(sample._asdict().keys()) == {"id", "float64"}
          assert sample.float64.size > 0
  
imports: import glob
  import itertools
  import numpy
  import pandas
  import pytest
  from pyarrow import parquet
  from petastorm import make_batch_reader, make_reader
  from petastorm.arrow_reader_worker import ArrowReaderWorker
  from petastorm.tests.test_common import create_test_scalar_dataset
  from petastorm.transform import TransformSpec
  from petastorm.unischema import UnischemaField
label_desc: Use image node_id 5 for calling a global function with example usage: test_specify_columns_to_read(scalar_dataset, reader_factory) without return types