diff --git a/CoreStoreTests/DynamicModelTests.swift b/CoreStoreTests/DynamicModelTests.swift
index 8b59e55..6ac863d 100644
--- a/CoreStoreTests/DynamicModelTests.swift
+++ b/CoreStoreTests/DynamicModelTests.swift
@@ -159,7 +159,7 @@ class DynamicModelTests: BaseTestDataTestCase {
                     XCTAssertTrue(person.pets.value.isEmpty)
                     
                     XCTAssertEqual(
-                        object_getClass(person.rawObject!).keyPathsForValuesAffectingValue(forKey: "displayName"),
+                        type(of: person.rawObject!).keyPathsForValuesAffectingValue(forKey: "displayName"),
                         ["title", "name"]
                     )
                     
diff --git a/Sources/CoreStoreSchema.swift b/Sources/CoreStoreSchema.swift
index aa17722..316923b 100644
--- a/Sources/CoreStoreSchema.swift
+++ b/Sources/CoreStoreSchema.swift
@@ -527,7 +527,7 @@ public final class CoreStoreSchema: DynamicSchema {
             let origSelector = #selector(NSManagedObject.keyPathsForValuesAffectingValue(forKey:))
             
             let metaClass: AnyClass = object_getClass(managedObjectClass)!
-            let origMethod = class_getClassMethod(managedObjectClass, origSelector)
+            let origMethod = class_getClassMethod(managedObjectClass, origSelector)!
             
             let origImp = method_getImplementation(origMethod)
             let newImp = imp_implementationWithBlock(keyPathsForValuesAffectingValue)