input: Write a function to find the largest difference between the largest and smallest numbers in a list.
  assert get_largest_diff([1, 2, 5, 4, 10, 8]) == 9
  assert get_largest_diff([10, 20, 30, 40, 50]) == 40
  assert get_largest_diff([5, 5, 5, 5]) == 0
output: def get_largest_diff(lst):
      return max(lst) - min(lst)