How can a Student object become more flexible?

"A more flexible approach might be to allow the construction of a Student instance without having to provide a course schedule. Instead, we could add a method that allowed the outside code to add a course to the student. For example,\n\n1 public function addCourse($c) {\n\n2 $this->schedule[] = $c;\n\n3 }\n\nThis adds some flexibility to our object, but removes the immutability property. Design is always a balance and compromise between competing considerations."