def _get_odim_sweep_group_names(nch, name):
    """Return sweep names.

    Returns source names and cfradial names.

    Parameters
    ----------
    nch : handle
        netCDF4 Dataset handle
    name : str
        Common part of source dataset names.

    Returns
    -------
    src : list
        list of source dataset names
    swg_grp_name : list
        list of corresponding cfradial sweep_group_name
    """
    src = [key for key in nch.groups.keys() if name in key]
    src.sort(key=lambda x: int(x[len(name) :]))
    swp_grp_name = ["sweep_{}".format(i) for i in range(1, len(src) + 1)]
    return src, swp_grp_name