Concatenated Words LeetCode solution in Python

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class Solution:
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    def findAllConcatenatedWordsInADict(self, words: List[str]) -> List[str]:
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        set_words = set(words)
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        def check(word, seen):
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            if word == "":
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                return True
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            for i in range(len(word) if seen else len(word) - 1):
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                if word[: i + 1] in set_words:
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                    if check(word[i + 1 :], seen | {word[: i + 1]}):
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                        return True
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            return False
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        return [word for word in words if check(word, set())]