Does Section 654 of the California Criminal Code bar a prosecution for the same act or omission under the same provision of law?

Section 654, subdivision (a) provides that "[a]n acquittal or conviction and sentence under any one [provision of law] bars a prosecution for the same act or omission under any other."⁵ In Kellett v. Superior Court (1966) 63 Cal.2d 822, 827, the court stated that "[w]hen, as here, the prosecution is or should be aware of more than one offense in which the same act or course of conduct plays a significant part, all such offenses must be prosecuted in a single proceeding unless joinder is prohibited or severance permitted for good cause. Failure to unite all such offenses will result in a bar to subsequent prosecution of any offense omitted if the initial proceedings culminate in either acquittal or conviction and sentence."