United States v. Castro, 599 F.3d 1050, 1054-1055 (9th Cir. Mar. 26, 2010) (at least under California law, an act cannot act "willfully" without also acting "knowingly" because California Penal Code 7(1) defines "willfully" as implying a purpose or willingness to commit an act, and one cannot willing commit an act without also knowing one is committing the act).