What is the test for establishing that there is a conspiracy to establish that there was one overall agreement?

To establish the existence of a single conspiracy, the government must prove that there was " 'one overall agreement' to perform various functions to achieve the objectives of the conspiracy." United States v. Arbelaez, 719 F.2d 1453, 1457 (9th Cir.1983) (quoting United States v. Zemek, 634 F.2d 1159, 1167 (9th Cir.1980) ). In turn, the determination of "one overall agreement" rests on an analysis of the "nature of the scheme; the identity of the participants; the quality, frequency, and duration of each conspirator's transactions; and the commonality of times and goals." Id. at 1458 (quoting United States v. Zemek, 634 F.2d at 1168).