class_docstr: Test the iteration functionality provided by vcf.VcfReader.
code: def test_fail_multiple_concurrent_iterations(self):
      range1 = ranges.parse_literal("chr3:100,000-500,000")
      reads = self.samples_reader.query(range1)
      for read in reads:
          pass
  
      r2 = self.samples_reader.query(range1)
      with self.assertRaisesRegexp(
          ValueError, "No underlying iterable. This "
      ):
          next(r2)
  
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 etils import epath
  from third_party.nucleus.io import vcf
  from third_party.nucleus.protos import reference_pb2
  from third_party.nucleus.protos import struct_pb2
  from third_party.nucleus.protos import variants_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 VcfReaderTests obj's underlying member method code with example usage: obj.test_fail_multiple_concurrent_iterations() without return types