What is the test for remand under section 654 of the California Criminal Code?

properly remand to permit the trial court to make the threshold determination of whether to exercise its discretion in defendant's favor [pursuant to Romero] without necessarily requiring resentencing unless the court does act favorably." (People v. Rodriguez (1998) 17 Cal.4th 253, 258, italics added.) As pointed out in People v. Alford (2010) 180 Cal.App.4th 1463, "[a] sentence must be imposed on each count, otherwise if the non-stayed sentence is vacated, either on appeal or in a collateral attack on the judgment, no valid sentence will remain." (Id. at p. 1469.) That is why, under section 654, a sentence is imposed but execution of that sentence is stayed because "if the unstayed sentence is reversed, a valid sentence remains extant." (People v. Alford, supra, at p. 1469, italics added.)