there is no federal statutory or common law of landlord and tenant. Powers I. United States Postal Serv., 671 F.2d 1041, 1042, 1045 (7th Cir.1982); Reed I. United States Postal Serv., 660 F.Supp. 178, 181 (D.Mass.1987). The question remains, therefore, what law applies in the absence of a federal rule on point. As the Supreme Co