                 for r in arr { insertArray.insert(r) }
             }
             for r in insertArray.sorted(by: { a, b in arc4random() & 0x1 == 0 }) {
-                try? btree.insert(r)
+                try! btree.insert(r)
             }
             for r in insertArray.sorted(by: { a, b in arc4random() & 0x1 == 0 }) {
                 XCTAssert(btree.contains(r))

            
            for i in interval { btree.replace(i) }
            
            let bheight2 = btree.height
            XCTAssert(bheight2 >= minHeight || bheight2 <= maxHeight, "\(bheight2) \(minHeight) \(maxHeight) \(i)")
            

            print(btree)
            btree.remove(hashValue: 2)
            print(btree)
            try! btree.insert(2)
            let interval = 0..<50
            for i in interval { try? btree.insert(i) }
            XCTAssert(btree.count == 50)
