Number of Equivalent Domino Pairs LeetCode solution in Python

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import math
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class Solution:
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    def numEquivDominoPairs(self, dominoes: List[List[int]]) -> int:
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        d = dict()
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        for i in dominoes:
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            i.sort()  # Just to make everything equal and comparable
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            if (
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                tuple(i) in d.keys()
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            ):  # In python, lists are unhashable so converted the list into tuples
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                d[tuple(i)] += 1
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            else:
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                d[tuple(i)] = 1
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        count = 0
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        for x, y in d.items():
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            if y > 1:
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                count += (
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                    y * (y - 1) // 2
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                )  # To check the number of pairs, if 2 elements pairs is 1,if 3 pair is 3 and so                                                                     on.....formula is n*n-1/2
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        return count