What is the test for reversing a federal district court's decision that excluded evidence of third party culpability in a criminal case?

The government argues that even if the district court erred in excluding the evidence of third-party culpability, the error was harmless. We disagree. "In the context of nonconstitutional error in criminal cases we must reverse ... unless it is more probable than not that the error was harmless." United States v. Seschillie , 310 F.3d 1208, 1215 (9th Cir. 2002) (internal quotation marks and citation omitted). "The government bears the burden of persuasion and ... [i]n cases of equipoise, we reverse." United States v. Liera , 585 F.3d 1237, 1244 (9th Cir. 2009) (internal quotation marks and citations omitted).