code: def combine_hla_fqs(hlas, out_file, data):
      
      if not utils.file_exists(out_file):
          with file_transaction(data, out_file) as tx_out_file:
              with open(tx_out_file, "w") as out_handle:
                  for hla_type, hla_fq in hlas:
                      if utils.file_exists(hla_fq):
                          with open(hla_fq) as in_handle:
                              shutil.copyfileobj(in_handle, out_handle)
      return out_file
docs: OptiType performs best on a combination of all extracted HLAs.