code: def _combine_files(tsv_files, work_dir, data):
      header = "\t".join(["caller", "sample", "chrom", "start", "end", "svtype",
                          "lof", "annotation", "split_read_support", "paired_support_PE", "paired_support_PR"])
      sample = dd.get_sample_name(data)
      out_file = os.path.join(work_dir, "%s-prioritize.tsv" % (sample))
      if not utils.file_exists(out_file):
          with file_transaction(data, out_file) as tx_out_file:
              tmpdir = os.path.dirname(tx_out_file)
              input_files = " ".join(tsv_files)
              sort_cmd = bedutils.get_sort_cmd(tmpdir)
              cmd = "{{ echo '{header}'; cat {input_files} | {sort_cmd} -k3,3 -k4,4n; }} > {tx_out_file}"
              do.run(cmd.format(**locals()), "Combine prioritized from multiple callers")
      return out_file