input: Write a function to find the closest value to a target in a list.
  assert find_closest_value([1, 3, 7, 8, 9], 5) == 3
  assert find_closest_value([2, 5, 6, 7, 8, 8], 9) == 8
  assert find_closest_value([-1, -3, -8, 2, 4], -4) == -3
output: def find_closest_value(lst, target):
      return min(lst, key=lambda x: abs(x - target))