code: def _datatarget_defaults(args, default_args):
      
      default_data = default_args.get("datatarget", [])
      # back-compatible toolplus specifications
      for x in default_args.get("toolplus", []):
          val = None
          if x == "data":
              val = "gemini"
          elif x in ["cadd", "dbnsfp", "dbscsnv", "kraken", "gnomad"]:
              val = x
          if val and val not in default_data:
              default_data.append(val)
      new_val = getattr(args, "datatarget")
      for x in default_data:
          if x not in new_val:
              new_val.append(x)
      has_std_target = False
      std_targets = ["variation", "rnaseq", "smallrna"]
      for target in std_targets:
          if target in new_val:
              has_std_target = True
              break
      if not has_std_target:
          new_val = new_val + std_targets
      setattr(args, "datatarget", new_val)
      return args
docs: Set data installation targets, handling defaults.
  
      Sets variation, rnaseq, smallrna as default targets if we're not
      isolated to a single method.
  
      Provides back compatibility for toolplus specifications.