message: Update binary-tree-vertical-order-traversal.py
  Error due to unused triple-quoted string literal
diff: @@ -15,7 +15,6 @@ class Solution(object):
  :type root: TreeNode
  :rtype: List[List[int]]
  """
  - """
  cols = collections.defaultdict(list)
  queue = [(root, 0)]
  for node, i in queue:
  