What is the test for impeaching a witness?

either helps the defendant or hurts the prosecution, as by impeaching one of its witnesses. [Citation.]" (In re Sassounian (1995) 9 Cal.4th 535, 544.) Impeachment evidence is not material if it adds "little to the cumulative impact of the other impeachment evidence." (People v. Dickey, supra, 35 Cal.4th at p. 908.)

"'[E]vidence that is presented at trial is not considered suppressed, regardless of whether or not it had previously been disclosed during discovery.'" (People v. Verdugo (2010) 50 Cal.4th 263, 281.)

b. Facts