message: Update populating-next-right-pointers-in-each-node-ii.py
diff: # Time: O(n)
  # Space: O(1)
  -"""
  # Definition for a Node.
  class Node(object):
  def __init__(self, val=0, left=None, right=None, next=None):
  @@ -9,7 +8,7 @@ class Node(object):
  self.left = left
  self.right = right
  self.next = next
  -"""
  +
  class Solution(object):
  # @param root, a tree node
  