Added HW9.
Added HW9.


Former-commit-id: e14e6efb9dc2188799dec88f52368936f984d13c [formerly 3d9e0076bf7617bdcf88508e69561fc7f6c8206d]
Former-commit-id: e8756819e497dc53066108467401b21c3a54ee1e
justinbois/bebi103_utils