Binary Tree Level Order Traversal

[Gauravsharma-20]

Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).

Example 1:
Input: root = [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]

Example 2:

Input: root = [1]
Output: [[1]]
Example 3:

Input: root = []
Output: []

[Samiya-Nisar]

Sir,Can you please assign me this task!!