@Override
    public Course assignRoleSchoolToCourse(long roleId, long courseId) {
        RoleSchool specificRole = null;
        for(Person person : persons){
                List<RoleSchool> roles = (ArrayList<RoleSchool>)person.getRoles();
                for(RoleSchool role : roles){
                    if(role.getId() == roleId){
                        specificRole = role;
                    }
                }
            
        }
        for(Course course : courses){
            if(course.getId() == courseId){
                course.addRole(specificRole);
                return course;
            }
        }
        return null;
    }