input: from typing import List
  
  def diffHighestLowest(arr: List[int]) -> int:
      """Calculate the difference between the highest and lowest values in a given list of integers.
      >>> diffHighestLowest([12, 24, 3, 8, -1])
      25
      >>> diffHighestLowest([10, 0, 20, 40, -5])
      45
      """
output:     if not arr:
          return 0
      return max(arr) - min(arr)