More flex data unpack

fastai fastai dev
1

as addition to Untar_data requires .tgz file ending
and COCO dataset is a .zip file. May be better implement more general solution? Something like:

def unzip(fname: Path, dest: Optional[PathOrStr] = None):
    dest = fname.parent if dest is None else dest
    with zipfile.ZipFile(fname) as f:
        f.extractall(dest)


def untar(fname: Path, dest: Optional[PathOrStr] = None):
    dest = fname.parent if dest is None else dest
    tarfile.open(fname, "r:gz").extractall(dest)


UNPACKERS = {".zip": unzip, ".tar": untar, ".tar.gz": untar}


def unpack(url: str, fname: PathOrStr = None):
    fname = Config.data_path()/(fname or url.split("/")[-1])
    suffix = "".join(fname.suffixes)
    if not fname.exists():
        download_data(url, fname)
        UNPACKERS[suffix](fname)
    return fname