code: def run_scalpel(align_bams, items, ref_file, assoc_files, region=None,
                    out_file=None):
      
      if region is None:
          message = ("A region must be provided for Scalpel")
          raise ValueError(message)
      if is_paired_analysis(align_bams, items):
          call_file = _run_scalpel_paired(align_bams, items, ref_file,
                                            assoc_files, region, out_file)
      else:
          call_file = _run_scalpel_caller(align_bams, items, ref_file,
                                            assoc_files, region, out_file)
      return call_file
docs: Run Scalpel indel calling, either paired tumor/normal or germline calling.