What is the test for determining whether a defendant can be convicted of a charge of possession of a controlled substance based upon the type of substance in the package?

For example, if the substance in the red-taped cellophane-wrapped package was proven to be a non-controlled substance, Vargas could only have been convicted of attempted importation of cocaine and attempted possession of cocaine with intent to distribute, both violations of 21 U.S.C. 846. See United States v. Steward, 16 F.3d 317, 320 (9th Cir.1994) (finding that a defendant could be convicted for attempted sale of a controlled substance based upon his completed sale of a non-controlled substance which he believed to be controlled). Thus, the precise type of substance was a necessary element for each importation.