code: def _get_validate_plotdata_yaml(grading_file, data):
      
      with open(grading_file) as in_handle:
          grade_stats = yaml.safe_load(in_handle)
      for sample_stats in grade_stats:
          sample = sample_stats["sample"]
          for vtype, cat, val in _flatten_grading(sample_stats):
              yield [sample, variant.get("variantcaller", ""),
                     vtype, cat, val]
docs: Retrieve validation plot data from grading YAML file (old style).