code: def _prep_config(items, paired, work_dir):
      
      assert utils.which("configManta.py"), "Could not find installed configManta.py"
      out_file = os.path.join(work_dir, "runWorkflow.py")
      if not utils.file_exists(out_file) or _out_of_date(out_file):
          config_script = os.path.realpath(utils.which("configManta.py"))
          cmd = [utils.get_program_python("configManta.py"), config_script]
          if paired:
              if paired.normal_bam:
                  cmd += ["--normalBam=%s" % paired.normal_bam, "--tumorBam=%s" % paired.tumor_bam]
              else:
                  cmd += ["--tumorBam=%s" % paired.tumor_bam]
          else:
              cmd += ["--bam=%s" % dd.get_align_bam(data) for data in items]
          data = paired.tumor_data if paired else items[0]
          cmd += ["--referenceFasta=%s" % dd.get_ref_file(data), "--runDir=%s" % work_dir]
          if dd.get_coverage_interval(data) not in ["genome"]:
              cmd += ["--exome"]
          for region in _maybe_limit_chromosomes(data):
              cmd += ["--region", region]
          resources = config_utils.get_resources("manta", data["config"])
          if resources.get("options"):
              cmd += [str(x) for x in resources["options"]]
          # If we are removing polyX, avoid calling on small indels which require
          # excessively long runtimes on noisy WGS runs
          if "polyx" in dd.get_exclude_regions(data):
              cmd += ["--config", _prep_streamlined_config(config_script, work_dir)]
          do.run(cmd, "Configure manta SV analysis")
      return out_file
docs: Run initial configuration, generating a run directory for Manta.