code: def test_bed_iterate(self):
      with bed_reader.BedReader.from_file(
          self.bed, self.options
      ) as reader:
          self.assertEqual(reader.header.num_fields, 12)
          iterable = reader.iterate()
          self.assertIsInstance(
              iterable, clif_postproc.WrappedCppIterable
          )
          actual = list(iterable)
          self.assertLen(actual, 2)
          self.assertEqual(actual[0], self.first)
  
      zreader = bed_reader.BedReader.from_file(
          self.zipped_bed, bed_pb2.BedReaderOptions()
      )
      self.assertEqual(zreader.header.num_fields, 12)
      with zreader:
          ziterable = zreader.iterate()
          self.assertIsInstance(
              ziterable, clif_postproc.WrappedCppIterable
          )
          zactual = list(ziterable)
          self.assertLen(zactual, 2)
          self.assertEqual(zactual[0], self.first)
  
file_path: deepvariant/third_party/nucleus/io/python/bed_reader_wrap_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import absltest
  from absl.testing import parameterized
  from third_party.nucleus.io import clif_postproc
  from third_party.nucleus.io.python import bed_reader
  from third_party.nucleus.protos import bed_pb2
  from third_party.nucleus.testing import test_utils
label_desc: Use image node_id 2 for calling the BedReaderTest obj's underlying member method code with example usage: obj.test_bed_iterate() without return types