def string(dfx, *args):
    x = copy(dfx); df = copy(dfx)
    if type(df) == pd.DataFrame:
        x, col = argcheck(df, args)
        for y in col:
            x[y] = x[y].astype("str")+"*"
        return x
    elif type(df) == pd.Series: 
        df = df.astype("str")+"*"
        return df
    else: return str(df)