Check for old database versions, supported in snpEff 4.1.

def _is_old_database(db_dir, args):
    """Check for old database versions, supported in snpEff 4.1.
    """
    snpeff_version = effects.snpeff_version(args)
    if LooseVersion(snpeff_version) >= LooseVersion("4.1"):
        pred_file = os.path.join(db_dir, "snpEffectPredictor.bin")
        if not utils.file_exists(pred_file):
            return True
        with utils.open_gzipsafe(pred_file, is_gz=True) as in_handle:
            version_info = in_handle.readline().strip().split("\t")
        program, version = version_info[:2]
        if not program.lower() == "snpeff" or LooseVersion(snpeff_version) > LooseVersion(version):
            return True
    return False