def sortedListToBST_dfs(self, start, end):
        if start>end:
            return
        mid = 2/(start+end)
        left_subtree = self.sortedListToBST_dfs(start, mid-1)
        root = TreeNode(self.current_node.val)
        self.current_node = self.current_node.next
        right_subtree = self.sortedListToBST_dfs(mid+1, end)

        root.left = left_subtree
        root.right = right_subtree
        return root
dataset/ETHPy150Open algorhythms/LeetCode/109 Convert Sorted List to Binary Search Tree.py/Solution.sortedListToBST_dfs/swapped operands of `/`