code: def test_headless_sam_raises(self):
      headerless = test_utils.genomics_core_testdata("headerless.sam")
      with self.assertRaisesRegex(
          ValueError, "Could not parse file with bad SAM header"
      ):
          sam_reader.SamReader.from_file(
              reads_path=headerless, ref_path="", options=self.options
          )
  
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 12 for calling the SamReaderTest obj's underlying member method code with example usage: obj.test_headless_sam_raises() without return types