input: from typing import List
  
  def sum_subsequence_powers(nums: List[int], k: int) -> int:
      """
      Given an integer list nums of length n and a positive integer k.
  
      Define the power of a subsequence as the minimum absolute difference between any two elements within it.
  
      Compute the sum of powers for all subsequences of nums where the subsequence's length is equal to k.
  
      Return the result modulo 10^9 + 7 due to potentially large answers.
  
      Examples:
      >>> nums = [1, 2, 3, 4], k = 3
      4
      >>> nums = [2, 2], k = 2
      0
      >>> nums = [4, 3, -1], k = 2
      10
  
      Constraints:
      2 <= len(nums) == n <= 50
      -10^8 <= nums[i] <= 10^8 
      2 <= k <= n
      """
output:     
      import itertools
  
      MOD = 10**9 + 7
  
      def power_of_subsequence(subseq):
          return abs(max(subseq) - min(subseq))
  
      def nCr(n, r):
          numerator = 1
          for i in range(r):
              numerator *= (n - i)
          denominator = 1
          for i in range(1, r + 1):
              denominator *= i
          return numerator // denominator
  
      subsequences = list(itertools.combinations(nums, k))
      total_sum = 0
  
      for subseq in subsequences:
          total_sum = (total_sum + power_of_subsequence(subseq)) % MOD
  
      return total_sum
  