code: def _pick_lead_item(items):
      
      if vcfutils.is_paired_analysis([dd.get_align_bam(x) for x in items], items):
          for data in items:
              if vcfutils.get_paired_phenotype(data) == "tumor":
                  return data
          raise ValueError("Did not find tumor sample in paired tumor/normal calling")
      else:
          return items[0]
docs: Pick single representative sample for batch calling to attach calls to.
  
      For cancer samples, attach to tumor.