Hi, here's your problem today. This problem was recently asked by Microsoft:

A k-ary tree is a tree with k-children, and a tree is symmetrical if the data of the left side of the tree is the same as the right side of the tree.

Here's an example of a symmetrical k-ary tree.
<pre>
        4
     /     \
    3        3
  / | \    / | \
9   4  1  1  4  9
</pre>
Given a k-ary tree, figure out if the tree is symmetrical.

Here is a starting point:

<pre lang=py>
class Node():
  def __init__(self, value, children=[]):
    self.value = value
    self.children = children

def is_symmetric(root):
  # Fill this in.

tree = Node(4)
tree.children = [Node(3), Node(3)]
tree.children[0].children = [Node(9), Node(4), Node(1)]
tree.children[1].children = [Node(1), Node(4), Node(9)]
print is_symmetric(tree)
# True
</pre>