     
     func testIndexBasedUpdateMethodWithNewUniqueKey() {
         var orderedDictionary: OrderedDictionary<String, Int> = ["A": 1, "B": 2, "C": 3]
-        let previousElement = try! orderedDictionary.update((key: "D", value: 4), at: 1)
+        let previousElement = orderedDictionary.update((key: "D", value: 4), at: 1)
         
         XCTAssertEqual(orderedDictionary.count, 3)
         XCTAssertTrue(previousElement! == ("B", 2))

    
    func testIndexBasedUpdateMethodByReplacingSameKey() {
        var orderedDictionary: OrderedDictionary<String, Int> = ["A": 1, "B": 2, "C": 3]
        let previousElement = try! orderedDictionary.update((key: "B", value: 42), at: 1)
        
        XCTAssertEqual(orderedDictionary.count, 3)
        XCTAssertTrue(previousElement! == ("B", 2))

    }
    
    func testIndexBasedInsertionWithDuplicateKey() {
        let orderedDictionary: OrderedDictionary<String, Int> = ["A": 1, "B": 2, "C": 3]
        let invalidElement = (key: "A", value: 42)
        
        XCTAssertFalse(orderedDictionary.canInsert(invalidElement))
    }
    
    // ======================================================= //
