code: def _useful_basename(data):
      
      names = dd.get_batches(data)
      if not names:
          names = [dd.get_sample_name(data)]
      batch_name = names[0]
      return "%s-%s" % (batch_name, data["sv"]["variantcaller"])
docs: Provide a useful file basename for outputs, referencing batch/sample and caller.