} public function add(Student $student) { if (!$this->contains($student)) { $this->students[] = $student; } } public function contains(Student $student) { foreach ($this->students as $s) { if ($s->getId() == $student->getId()) { return true; } } return false; } public function getIterator() { return $this->students->getIterator(); } } $students = new StudentList(); $students->add(new Student('01234123', 'Joe')); $students->add(new Student('00000014', 'Bob')); $students->add(new Student('00000014', 'Foo')); foreach ($students as $student) { echo $student, "\n"; } ?> ===DONE===