Concise Python BFS solution
\nclass Solution:\n    def findBottomLeftValue(self, root: TreeNode) -> int:\n        last = None\n        queue = deque()\n        queue.append(root)\n        
```\nclass Solution:\n    def findBottomLeftValue(self, root: TreeNode) -> int:\n        last = None\n        queue = deque()\n        queue.append(root)\n        \n        while queue:\n            node = queue.popleft()\n            last = node.val\n            if node.right:\n                queue.append(node.right)\n            if node.left:\n                queue.append(node.left)\n        \n        return last\n```
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