def get_path(url, root_dir, md5sum=None, check_exist=True):
    """ Download from given url to root_dir.
    if file or directory specified by url is exists under
    root_dir, return the path directly, otherwise download
    from url and decompress it, return the path.

    url (str): download url
    root_dir (str): root dir for downloading, it should be
                    WEIGHTS_HOME or DATASET_HOME
    md5sum (str): md5 sum of download package
    """
    # parse path after download to decompress under root_dir
    fullpath = map_path(url, root_dir)

    # For same zip file, decompressed directory name different
    # from zip file name, rename by following map
    decompress_name_map = {
        "VOCtrainval_11-May-2012": "VOCdevkit/VOC2012",
        "VOCtrainval_06-Nov-2007": "VOCdevkit/VOC2007",
        "VOCtest_06-Nov-2007": "VOCdevkit/VOC2007",
        "annotations_trainval": "annotations"
    }
    for k, v in decompress_name_map.items():
        if fullpath.find(k) >= 0:
            fullpath = osp.join(osp.split(fullpath)[0], v)

    if osp.exists(fullpath) and check_exist:
        if not osp.isfile(fullpath) or \
                _check_exist_file_md5(fullpath, md5sum, url):
            logger.debug("Found {}".format(fullpath))
            return fullpath, True
        else:
            os.remove(fullpath)

    fullname = _download_dist(url, root_dir, md5sum)

    # new weights format which postfix is 'pdparams' not
    # need to decompress
    if osp.splitext(fullname)[-1] not in ['.pdparams', '.yml', '.ttf']:
        _decompress_dist(fullname)

    return fullpath, False
 Download from given url to root_dir.
    if file or directory specified by url is exists under
    root_dir, return the path directly, otherwise download
    from url and decompress it, return the path.

    url (str): download url
    root_dir (str): root dir for downloading, it should be
                    WEIGHTS_HOME or DATASET_HOME
    md5sum (str): md5 sum of download package
    
ppdet/utils/download.py