class Solution(object):
    def hasPathSum(self, root, sum):
        """
 :type root: TreeNode
 :type sum: int
 :rtype: bool
 """
 if not root:
 return False

 if root and not root.left and not root.right:
 return sum == root.val
 if self.hasPathSum(root.left,sum-root.val):
 return True
 if self.hasPathSum(root.right,sum-root.val):
 return True
 return False