             
             for i in interval { btree.replace(i) }
             
+            let a = (try? btree.insert(47)) == nil
+            XCTAssert(a)
+            
             let bheight2 = btree.height
             XCTAssert(bheight2 >= minHeight || bheight2 <= maxHeight, "\(bheight2) \(minHeight) \(maxHeight) \(i)")
             

                XCTAssert(!btree.contains(r))
            }
            
            try? btree.insert(2)
            print(btree)
        }
    }

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