Loud and Rich LeetCode solution in Python

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class Solution:
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    def loudAndRich(self, richer: List[List[int]], quiet: List[int]) -> List[int]:
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        length = len(quiet)
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        arr = [i for i in range(length)]
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        indegree = [0 for _ in range(length)]
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        graph = collections.defaultdict(list)
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        dq = collections.deque([])
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        for a, b in richer:
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            # Note that the graph is uni-directional
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            graph[a].append(b)
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            indegree[b] += 1
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        for i in range(length):
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            if not indegree[i]:
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                dq.append(i)
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        while dq:
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            node = dq.popleft()
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            for vertex in graph[node]:
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                indegree[vertex] -= 1
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                if quiet[arr[node]] < quiet[arr[vertex]]:
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                    arr[vertex] = arr[node]
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                if not indegree[vertex]:
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                    dq.append(vertex)
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        return arr