def levelOrder(self,root):
        #Write your code here
      levelq = []
      levelq.append(root)
      if root != None:
          while levelq != []:
              tmp = levelq.pop(0)
              print(tmp.data, end=' ')

              if tmp.left != None:
                  levelq.append(tmp.left)
              if tmp.right != None:
                  levelq.append(tmp.right)