def METHOD_NAME(args, run_db, cal_db):
    """
    make it easier to call this from argparse:
        arg("-ds", nargs='*', action="store", help="load runs for a DS")
        arg("-r", "--run", nargs=1, help="load a single run")
    """
    from pygama import DataSet
    if args["ds"]:
        ds_lo = int(args["ds"][0])
        try:
            ds_hi = int(args["ds"][1])
        except:
            ds_hi = None
        ds = DataSet(ds_lo, ds_hi, md=run_db, cal=cal_db, v=args["verbose"])
    if args["run"]:
        ds = DataSet(run=int(args["run"][0]), md=run_db, cal=cal_db,
                     v=args["verbose"])
    return ds