code: def test_sam_contigs(self):
      reader = sam_reader.SamReader.from_file(
          reads_path=self.bam, ref_path="", options=self.options
      )
      with reader:
          self.assertEqual(
              [
                  reference_pb2.ContigInfo(
                      name="chrM", pos_in_fasta=0, n_bases=16571
                  ),
                  reference_pb2.ContigInfo(
                      name="chr1", pos_in_fasta=1, n_bases=249250621
                  ),
                  reference_pb2.ContigInfo(
                      name="chr2", pos_in_fasta=2, n_bases=243199373
                  ),
                  reference_pb2.ContigInfo(
                      name="chr3", pos_in_fasta=3, n_bases=198022430
                  ),
                  reference_pb2.ContigInfo(
                      name="chr4", pos_in_fasta=4, n_bases=191154276
                  ),
                  reference_pb2.ContigInfo(
                      name="chr5", pos_in_fasta=5, n_bases=180915260
                  ),
                  reference_pb2.ContigInfo(
                      name="chr6", pos_in_fasta=6, n_bases=171115067
                  ),
                  reference_pb2.ContigInfo(
                      name="chr7", pos_in_fasta=7, n_bases=159138663
                  ),
                  reference_pb2.ContigInfo(
                      name="chr8", pos_in_fasta=8, n_bases=146364022
                  ),
                  reference_pb2.ContigInfo(
                      name="chr9", pos_in_fasta=9, n_bases=141213431
                  ),
                  reference_pb2.ContigInfo(
                      name="chr10", pos_in_fasta=10, n_bases=135534747
                  ),
                  reference_pb2.ContigInfo(
                      name="chr11", pos_in_fasta=11, n_bases=135006516
                  ),
                  reference_pb2.ContigInfo(
                      name="chr12", pos_in_fasta=12, n_bases=133851895
                  ),
                  reference_pb2.ContigInfo(
                      name="chr13", pos_in_fasta=13, n_bases=115169878
                  ),
                  reference_pb2.ContigInfo(
                      name="chr14", pos_in_fasta=14, n_bases=107349540
                  ),
                  reference_pb2.ContigInfo(
                      name="chr15", pos_in_fasta=15, n_bases=102531392
                  ),
                  reference_pb2.ContigInfo(
                      name="chr16", pos_in_fasta=16, n_bases=90354753
                  ),
                  reference_pb2.ContigInfo(
                      name="chr17", pos_in_fasta=17, n_bases=81195210
                  ),
                  reference_pb2.ContigInfo(
                      name="chr18", pos_in_fasta=18, n_bases=78077248
                  ),
                  reference_pb2.ContigInfo(
                      name="chr19", pos_in_fasta=19, n_bases=59128983
                  ),
                  reference_pb2.ContigInfo(
                      name="chr20", pos_in_fasta=20, n_bases=63025520
                  ),
                  reference_pb2.ContigInfo(
                      name="chr21", pos_in_fasta=21, n_bases=48129895
                  ),
                  reference_pb2.ContigInfo(
                      name="chr22", pos_in_fasta=22, n_bases=51304566
                  ),
                  reference_pb2.ContigInfo(
                      name="chrX", pos_in_fasta=23, n_bases=155270560
                  ),
                  reference_pb2.ContigInfo(
                      name="chrY", pos_in_fasta=24, n_bases=59373566
                  ),
              ],
              list(reader.header.contigs),
          )
  
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 sam_reader
  from third_party.nucleus.protos import reads_pb2
  from third_party.nucleus.protos import reference_pb2
  from third_party.nucleus.testing import test_utils
  from third_party.nucleus.util import ranges
label_desc: Use image node_id 5 for calling the SamReaderTest obj's underlying member method code with example usage: obj.test_sam_contigs() without return types