@Override
    public RoleSchool addRoleSchool(String json, long id) {
        RoleSchool role = trans.fromJson(json, RoleSchool.class);
        if (json.contains("Teacher")) {
            role = trans.fromJson(json, Teacher.class);
        }
        if (json.contains("Student")) {
            role = trans.fromJson(json, Student.class);
        }
        if (json.contains("AssistentTeacher")) {
            role = trans.fromJson(json, AssistentTeacher.class);
        }

        em.getTransaction().begin();
        Person person = em.find(Person.class, id);
        if (person != null && role != null) {
            person.addRole(role);
            //== Maybe use persist, or merge
        }
        em.getTransaction().commit();

        return role;
    }