code: def _get_bad_field_name(field_list):
      """Grab first name from list of valid fields, append random characters to it to get an invalid
      field name."""
      bad_field = field_list[0]
      while bad_field in field_list:
          bad_field += "VR46"
      return bad_field
  
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 2 for calling a global function with example usage: _get_bad_field_name(field_list) and returns: bad_field