code: def test_vaf_histograms_by_genotype(self):
      variant_stats_lite = collections.namedtuple(
          "variant_stats_lite", ["genotype", "vaf"]
      )
      variant_stats = [
          variant_stats_lite(genotype="[0, 0]", vaf=0),
          variant_stats_lite(genotype="[1, 1]", vaf=1),
          variant_stats_lite(genotype="[0, 1]", vaf=0.5),
          variant_stats_lite(genotype="[0, 1]", vaf=0.5),
          variant_stats_lite(genotype="[0, 0]", vaf=0.08),
          variant_stats_lite(genotype="[0, 0]", vaf=0.19),
          variant_stats_lite(genotype="[0, 1]", vaf=0.45),
          variant_stats_lite(genotype="[0, 1]", vaf=0.65),
      ]
      # s = bin_start, e = bin_end, c = count
      truth_histograms = """
      {
        "[0, 1]": [{"c": 0, "e": 0.1, "s": 0.0}, {"c": 0, "e": 0.2, "s": 0.1}, {"c": 0, "e": 0.3, "s": 0.2}, {"c": 0, "e": 0.4, "s": 0.3}, {"c": 1, "e": 0.5, "s": 0.4}, {"c": 2, "e": 0.6, "s": 0.5}, {"c": 1, "e": 0.7, "s": 0.6}, {"c": 0, "e": 0.8, "s": 0.7}, {"c": 0, "e": 0.9, "s": 0.8}, {"c": 0, "e": 1.0, "s": 0.9}],
        "[1, 1]": [{"c": 0, "e": 0.1, "s": 0.0}, {"c": 0, "e": 0.2, "s": 0.1}, {"c": 0, "e": 0.3, "s": 0.2}, {"c": 0, "e": 0.4, "s": 0.3}, {"c": 0, "e": 0.5, "s": 0.4}, {"c": 0, "e": 0.6, "s": 0.5}, {"c": 0, "e": 0.7, "s": 0.6}, {"c": 0, "e": 0.8, "s": 0.7}, {"c": 0, "e": 0.9, "s": 0.8}, {"c": 1, "e": 1.0, "s": 0.9}],
        "[0, 0]": [{"c": 2, "e": 0.1, "s": 0.0}, {"c": 1, "e": 0.2, "s": 0.1}, {"c": 0, "e": 0.3, "s": 0.2}, {"c": 0, "e": 0.4, "s": 0.3}, {"c": 0, "e": 0.5, "s": 0.4}, {"c": 0, "e": 0.6, "s": 0.5}, {"c": 0, "e": 0.7, "s": 0.6}, {"c": 0, "e": 0.8, "s": 0.7}, {"c": 0, "e": 0.9, "s": 0.8}, {"c": 0, "e": 1.0, "s": 0.9}],
        "[-1, -1]": [{"c": 0, "e": 0.5, "s": 0.0}, {"c": 0, "e": 1.0, "s": 0.5}],
        "[1, 2]": [{"c": 0, "e": 0.5, "s": 0.0}, {"c": 0, "e": 1.0, "s": 0.5}]
        }
      """
      self.assertEqual(
          vcf_stats._vaf_histograms_by_genotype(variant_stats),
          json.loads(truth_histograms),
      )
  
imports: import collections
  import json
  import os
  import tempfile
  from absl.testing import absltest
  from absl.testing import parameterized
  import tensorflow
  from deepvariant import testdata
  from deepvariant import vcf_stats
  from third_party.nucleus.io import vcf
  from third_party.nucleus.testing import test_utils
  from third_party.nucleus.util import variant_utils
  from third_party.nucleus.util import variantcall_utils
label_desc: Use image node_id 5 for calling the VcfStatsTest obj's underlying member method code with example usage: obj.test_vaf_histograms_by_genotype() without return types