code: def _run_qsnp_paired(align_bams, items, ref_file, assoc_files,
                       region=None, out_file=None):
      
      config = items[0]["config"]
      if out_file is None:
          out_file = "%s-paired-variants.vcf" % os.path.splitext(align_bams[0])[0]
      if not utils.file_exists(out_file):
          out_file = out_file.replace(".gz", "")
          with file_transaction(config, out_file) as tx_out_file:
              with tx_tmpdir(config) as tmpdir:
                  with utils.chdir(tmpdir):
                      paired = get_paired_bams(align_bams, items)
                      qsnp = config_utils.get_program("qsnp", config)
                      resources = config_utils.get_resources("qsnp", config)
                      mem = " ".join(resources.get("jvm_opts", ["-Xms750m -Xmx4g"]))
                      qsnp_log = os.path.join(tmpdir, "qsnp.log")
                      qsnp_init = os.path.join(tmpdir, "qsnp.ini")
                      if region:
                          paired = _create_bam_region(paired, region, tmpdir)
                      _create_input(paired, tx_out_file, ref_file, assoc_files['dbsnp'], qsnp_init)
                      cl = ("{qsnp} {mem} -i {qsnp_init} -log {qsnp_log}")
                      do.run(cl.format(**locals()), "Genotyping paired variants with Qsnp", {})
          out_file = _filter_vcf(out_file)
          out_file = bgzip_and_index(out_file, config)
      return out_file
docs: Detect somatic mutations with qSNP.
  
      This is used for paired tumor / normal samples.