code: def _handle_precalled(data):
      
      if data.get("vrn_file") and not cwlutils.is_cwl_run(data):
          vrn_file = data["vrn_file"]
          if isinstance(vrn_file, (list, tuple)):
              assert len(vrn_file) == 1
              vrn_file = vrn_file[0]
          precalled_dir = utils.safe_makedir(os.path.join(dd.get_work_dir(data), "precalled"))
          ext = utils.splitext_plus(vrn_file)[-1]
          orig_file = os.path.abspath(vrn_file)
          our_vrn_file = os.path.join(precalled_dir, "%s-precalled%s" % (dd.get_sample_name(data), ext))
          utils.copy_plus(orig_file, our_vrn_file)
          data["vrn_file"] = our_vrn_file
      return data
docs: Copy in external pre-called variants fed into analysis.
  
      Symlinks for non-CWL runs where we want to ensure VCF present
      in a local directory.