Array Nesting LeetCode solution in Python

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class Solution:
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    def arrayNesting(self, nums: List[int]) -> int:
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        max_len = 0
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        visited = set()
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        def dfs(nums, index, dfs_visited):
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            if index in dfs_visited:
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                return len(dfs_visited)
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            # add the index to dfs_visited and visited
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            visited.add(index)
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            dfs_visited.add(index)
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            return dfs(nums, nums[index], dfs_visited)
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        for i in range(len(nums)):
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            if i not in visited:
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                max_len = max(max_len, dfs(nums, i, set()))
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        return max_len