input: from typing import List
  
  def compute_subsequence_powers(nums: List[int], k: int) -> int:
      """
      Given a list of integers nums and a positive integer k, calculate the following:
  
      Define the power of a subsequence as the minimum absolute difference between any pair of elements within it.
  
      Compute the total sum of the powers for all k-length subsequences of nums.
  
      As results could be large, return the total modulo 10^9 + 7.
  
      Examples:
      >>> nums = [1,2,3,4], k = 3
      4
      >>> nums = [2,2], k = 2
      0
      >>> nums = [4,3,-1], k = 2
      10
  
      Constraints:
      2 <= n == len(nums) <= 50
      -10^8 <= nums[i] <= 10^8 
      2 <= k <= n
      """
output:     
      from itertools import combinations
  
      MOD = 10**9 + 7
  
      total_sum = 0
  
      for subsequence in combinations(nums, k):
          min_absolute_diff = float('inf')
          for i in range(k):
              for j in range(i+1, k):
                  min_absolute_diff = min(min_absolute_diff, abs(subsequence[i] - subsequence[j]))
          total_sum = (total_sum + min_absolute_diff) % MOD
  
      return total_sum
  