How have courts interpreted the parol evidence rule in the context of a claim for negligent misrepresentation?

In discharging its Erie obligation to ascertain and apply state substantive law, the district court is ordinarily bound by the decisions and dicta of the highest state court on the question. Dimidowich v. Bell & Howell, 803 F.2d 1473, 1482 (9th Cir.1986). Where, as here, the state court of last resort has offered no guidance, the district court must look to other sources, including published opinions from other jurisdictions. Cunha, 804 F.2d at 1424; Dimidowich, 803 F.2d at 1482. The district court failed to explain the basis for its conclusion that Idaho would apply the parol evidence rule to a claim for negligent misrepresentation. Again, however, we agree with the court's conclusion and affirm nevertheless.