lowest_common_ancestor_of_a_binary_tree.py

class Solution(object):
    def lowestCommonAncestor(self, root, p, q):

        if root is None or root == p or root == q:
            return root

        left = self.lowestCommonAncestor(root.left, p, q)
        right = self.lowestCommonAncestor(root.right, p, q)

        if left and right:
            return root

        return left if left else right