def combine_lbls(lbl, acfg_lbl):
    if (len(lbl) == 0):
        return acfg_lbl
    if (len(acfg_lbl) == 0):
        return lbl
    return ((lbl + '+') + acfg_lbl)
def combine_lbls(lbl, acfg_lbl):
    if (len(lbl) == 0):
        return acfg_lbl
    if (len(acfg_lbl) == 0):
        return lbl
    return ((lbl + '+') + acfg_lbl)