download aligns

def download_align(from_idx, to_idx, _params):
    """
    download aligns
    """
    succ = set()
    fail = set()
    for idx in range(from_idx, to_idx):
        name = 's' + str(idx)
        if idx == 0:
            continue
        script = "http://spandh.dcs.shef.ac.uk/gridcorpus/{nm}/align/{nm}.tar".format(nm=name)
        down_sc = 'cd {align_path} && wget {script} && \
                    tar -xvf {nm}.tar'.format(script=script,
                                              nm=name,
                                              align_path=_params['align_path'])
        try:
            print(down_sc)
            os.system(down_sc)
            succ.add(idx)
        except OSError as error:
            print(error)
            fail.add(idx)
    return (succ, fail)