Count All Valid Pickup and Delivery Options LeetCode solution in Python

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class Solution:
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    def countOrders(self, n: int) -> int:
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        total = 1
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        mod = 10**9 + 7
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        for k in reversed(range(2, n + 1)):
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            total = total * ((2 * k - 1) * (2 * k - 2) // 2 + 2 * k - 1)
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            total = total % mod
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        return total