I'm currently working on LeetCode problem [108. Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/):

> 
> Given an integer array `nums` where the elements are sorted in **ascending order**, convert *it to a **height-balanced** binary search tree*.
> 
> 
> A **height-balanced** binary tree is a binary tree in which the depth of the two subtrees of every node never differs by more than one.
> 
> 
> 

My code seems to be working fine but I don't know how to display the value *null* instead of *None* in my list. I need to print the BST in level order traversal. I'm looking for advice, hints or suggestions.

Input:

```
[-10,-3,0,5,9]

```

My current output:

```
[0, -3, 9, -10, None, 5, None]

```

Accepted output:

```
[0,-3,9,-10,null,5]

```

Here is my code:

```
from queue import Queue
from typing import Optional

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def sortedArrayToBST(nums: [int]) -> Optional[TreeNode]:
    nbNodes = len(nums)

    if nbNodes == 1:
        root = TreeNode()
        root.val = nums[0]
        return root
    elif nbNodes == 0:
        root = TreeNode()
        root.val = None
        return root

    middle = int(nbNodes / 2)
    root = TreeNode()
    root.val = nums[middle]
    leftList = []
    rightList = []
    j = middle + 1

    for i in range(middle):
        leftList.append(nums[i])

        if j != nbNodes:
            rightList.append(nums[j])
        j += 1

    root.left = sortedArrayToBST(leftList)
    root.right = sortedArrayToBST(rightList)
    return root

def levelorder(root):
    if root==None:
        return
    Q=Queue()
    Q.put(root)
    level_order_list = []
    while(not Q.empty()):
        node=Q.get()
        if node==None:
            continue
        level_order_list.append(node.val)
        Q.put(node.left)
        Q.put(node.right)
    print(level_order_list)

if __name__ == "__main__":
    container = [-10,-3,0,5,9]
    levelorder(sortedArrayToBST(container))

```