def _trna_annotation(data):
    """
    use tDRmapper to quantify tRNAs
    """
    trna_ref = op.join(dd.get_srna_trna_file(data))
    name = dd.get_sample_name(data)
    work_dir = utils.safe_makedir(os.path.join(dd.get_work_dir(data), "trna", name))
    in_file = op.basename(data["clean_fastq"])
    tdrmapper = os.path.join(os.path.dirname(sys.executable), "TdrMappingScripts.pl")
    perl_export = utils.get_perl_exports()
    if not file_exists(trna_ref) or not file_exists(tdrmapper):
        logger.info("There is no tRNA annotation to run TdrMapper.")
        return work_dir
    out_file = op.join(work_dir, in_file + ".hq_cs.mapped")
    if not file_exists(out_file):
        with tx_tmpdir(data) as txdir:
            with utils.chdir(txdir):
                utils.symlink_plus(data["clean_fastq"], op.join(txdir, in_file))
                cmd = ("{perl_export} && perl {tdrmapper} {trna_ref} {in_file}").format(**locals())
                do.run(cmd, "tRNA for %s" % name)
                for filename in glob.glob("*mapped*"):
                    shutil.move(filename, work_dir)
    return work_dir
use tDRmapper to quantify tRNAs