message: Update serialize-and-deserialize-binary-tree.py
  Just making it bit cleaner
diff: @@ -45,7 +45,7 @@ class Codec:
  def serializeHelper(node):
  if not node:
  vals.append('#')
  - else:
  + return
  vals.append(str(node.val))
  serializeHelper(node.left)
  serializeHelper(node.right)
  @@ -64,7 +64,6 @@ class Codec:
  val = next(vals)
  if val == '#':
  return None
  - else:
  node = TreeNode(int(val))
  node.left = deserializeHelper()
  node.right = deserializeHelper()
  