code: def test_invalid_nonref_genotype_count(self):
      zero_calls_variant = test_utils.make_variant()
      with self.assertRaisesRegex(
          ValueError, "Expected exactly one VariantCal"
      ):
          haplotypes._nonref_genotype_count(zero_calls_variant)
  
imports: import types
  from absl import flags
  from absl.testing import absltest
  from absl.testing import flagsaver
  from absl.testing import parameterized
  import numpy
  from third_party.nucleus.testing import test_utils
  from deepvariant import haplotypes
label_desc: Use image node_id 11 for calling the ResolveOverlappingVariantsTest obj's underlying member method code with example usage: obj.test_invalid_nonref_genotype_count() without return types