             print(btree)
             btree.insert(2)
             let interval = 0..<50
-            for i in interval {
-                btree.insert(i)
-            }
+            for i in interval { btree.insert(i) }
             XCTAssert(btree.count == 50)
             let minSize = (i + 1) / 2
             let minHeight = Int(round(log(51.0) / log(Double(i))) + 1) - 1

            let bheight = btree.height
            XCTAssert(bheight >= minHeight || bheight <= maxHeight, "\(bheight) \(minHeight) \(maxHeight) \(i)")
            print(btree)
            for i in interval.reversed() {
                // print(i, btree)
                XCTAssert(i == btree.remove(hashValue: i)!)

    
    func testBTree() {
        var btree = BTree<Int>(maxNodeSize: 5)!
        XCTAssert(BTree<Int>(maxNodeSize: 2) == nil)
        for i in [3, 6, 7] {
            btree = BTree<Int>(maxNodeSize: i)!
            btree.replace(2)
