A realty company (P) sued one of its tenants (D) for possession of the leased premises, and for payment of rent owed. The premises at issue had been in violation of certain sections of the Housing Code, with the knowledge of the realty company and the owner of the property, prior to the time that D signed her lease. The relevant Code sections provided that 'no persons shall rent or offer to rent any habitation...unless such habitation...are in a clean, safe and sanitary condition, in repair, and free from rodents or vermin.' The property at issue had an obstructed toilet, a broken railing, and insufficient ceiling height in the basement. D argued that, due to these violations, the lease contract was illegal and unenforceable. The trial court held that the lease was enforceable, and awarded P possession for nonpayment of rent. D appealed.