Shad Khan's suggestion to eliminate dummy node in level order traversal code using size of queue.

levelOrder.py

from collections import deque

class Solution(object):
    def levelOrder(self, root):
        q = deque()
       
        if(root != None):
            q.append(root)
        
        levels = []
        
        while(len(q) != 0):
            level = []
            lenq = len(q)
            
            for i in range(lenq):
                temp = q.popleft()
                
                if(temp.left != None):
                    q.append(temp.left)
                
                if(temp.right != None):
                    q.append(temp.right)
                
                level.append(temp.val)
            
            levels.append(level)    
        return levels