Finding 3-Digit Even Numbers LeetCode solution in Python

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class Solution:
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    def findEvenNumbers(self, digits: List[int]) -> List[int]:
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        hmap, res = defaultdict(int), []
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        for num in digits:
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            hmap[num] += 1  # counting frequency of digits of digits array
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        for num in range(100, 999, 2):  # step 2 because we need even numbers
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            checker = defaultdict(int)
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            for digit in str(num):
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                checker[int(digit)] += 1  # counting frequency of digits of num
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            # check if every digit in num is in digits array and its frequency is less than or equal to its frequency in digits array
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            if all(map(lambda x: x in hmap and checker[x] <= hmap[x], checker)):
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                res.append(num)
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        return res