def METHOD_NAME(self):
    model = AbstractModel()
    model.A = Set(initialize=[0])
    model.B = Set(initialize=[1])
    model.C = model.A | model.B
    M = ConcreteModel()
    M.x = Var([1, 2, 3])
    M.c = SOSConstraint(model.C, var=M.x, sos=1, index={0: [1, 2], 1: [2, 3]})