my BFS solution for python
class Solution(object):\n\n    def findBottomLeftValue(self, root):\n        """\n        :type root: TreeNode\n        :rtype: int\n        """\n        queue=
class Solution(object):\n\n    def findBottomLeftValue(self, root):\n        """\n        :type root: TreeNode\n        :rtype: int\n        """\n        queue=[root]; ans=0\n        while any(queue):\n            ans=queue[0].val\n            queue=[leaf for node in queue for leaf in (node.left,node.right) if leaf]\n        return ans
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