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class Solution:
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    def sumSubseqWidths(self, nums: List[int]) -> int:
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        nums.sort()
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        n = len(nums)
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        M = 10**9 + 7
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        res = 0
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        le = 1
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        re = pow(2, n - 1, M)
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        # by Fermat's Little Thm
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        # inverse of 2 modulo M
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        inv = pow(2, M - 2, M)
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        for num in nums:
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            res = (res + num * (le - re)) % M
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            le = (le * 2) % M
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            re = (re * inv) % M
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        return res