message: Update equal-tree-partition.py
diff: # Time: O(n)
  # Space: O(n)
  -# Given a binary tree with n nodes, your task is to check
  -# if it's possible to partition the tree to two trees which have the equal sum
  -# of values after removing exactly one edge on the original tree.
  -#
  -# Example 1:
  -# Input:
  -# 5
  -# / \
  -# 10 10
  -# / \
  -# 2 3
  -#
  -# Output: True
  -# Explanation:
  -# 5
  -# /
  -# 10
  -#
  -# Sum: 15
  -#
  -# 10
  -# / \
  -# 2 3
  -#
  -# Sum: 15
  -# Example 2:
  -# Input:
  -# 1
  -# / \
  -# 2 10
  -# / \
  -# 2 20
  -#
  -# Output: False
  -# Explanation: You can't split the tree into two trees with equal sum after removing exactly one edge on the tree.
  -# Note:
  -# The range of tree node value is in the range of [-100000, 100000].
  -# 1 <= n <= 10000
  -
  # Definition for a binary tree node.
  # class TreeNode(object):
  # def __init__(self, x):
  