Solution for above problem

@api.multi
def action_optional_flag_add(self):
    m1 = []
    for m in self.wizard:
        if m.services:
            aa = (m.services.id, m.check_box)
            m1.append(aa)
    count_num = dict(Counter(m1))
    res_allrecord = []
    for val in count_num:
        res_allrecord.append(val[0])
    list_res = list(set(res_allrecord))

    res_True = []
    for val in count_num:
        if val[1] != False:
            res_True.append(val)
    count = Counter([x for (x, y) in res_True])
    rec5 = dict(count)

    for list_val in list_res:
        if list_val not in rec5:
            rec5[list_val] = 0
    output = dict(count)

    for key, value in rec5.items():
        if value > 1:
            raise ValidationError("Please Select Atlease One Item from Flag")
        if value == 0:
            raise ValidationError("Please Select Atlease One Item from Flag")