Largest Time for Given Digits LeetCode solution in Python

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class Solution:
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    def largestTimeFromDigits(self, arr: List[int]) -> str:
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        res = ""
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        digit_freq = collections.Counter(arr)
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        # first digit
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        if 2 in arr and sum([digit_freq[d] for d in range(6)]) > 2:
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            res += "2"
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            arr.remove(2)
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        else:
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            for digit in [1, 0]:
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                if digit in arr:
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                    res += str(digit)
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                    arr.remove(digit)
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                    break
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        # can't make 24-hour time
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        if len(res) == 0:
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            return ""
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        # second digit 0-3
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        if res == "2":
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            for digit in [3, 2, 1, 0]:
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                if digit in arr:
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                    res += str(digit)
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                    arr.remove(digit)
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                    break
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            # no 0-3 left in arr
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            if len(res) == 1:
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                return ""
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        # second digit 0-9
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        else:
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            for digit in range(9, -1, -1):
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                if digit in arr:
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                    res += str(digit)
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                    arr.remove(digit)
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                    break
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        res += ":"
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        for digit in range(5, -1, -1):
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            if digit in arr:
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                res += str(digit)
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                arr.remove(digit)
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                break
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        if len(res) == 3:
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            return ""
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        for digit in range(9, -1, -1):
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            if digit in arr:
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                res += str(digit)
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                return res