code: def _add_supplemental_bams(data):
      
      file_key = "work_bam"
      if data.get(file_key):
          for supext in ["disc", "sr"]:
              base, ext = os.path.splitext(data[file_key])
              test_file = "%s-%s%s" % (base, supext, ext)
              if os.path.exists(test_file):
                  sup_key = file_key + "_plus"
                  if sup_key not in data:
                      data[sup_key] = {}
                  data[sup_key][supext] = test_file
      return data
docs: Add supplemental files produced by alignment, useful for structural
      variant calling.