ege has been (a) claimed and (b) not waived by the client. In re Grand Jury Proceedings, 517 F.2d 666, 670 (5th Cir. 1975), quoting United States v. United Shoe Machinery Corp., 89 F.Supp. 357, 358-59 (D. Mass.1950). The burden of proof is in the first instance on the individual asserting the privilege to demonstrate an at