input: Write a python function to find the k closest values to a given number x from a list.
  assert kClosestValues([4, 1, 7, 3, 8], 5, 3) == [4, 3, 7]
  assert kClosestValues([10, 22, 5, 14, 7], 8, 2) == [7, 10]
  assert kClosestValues([1, 2, 3, 4, 5], 3, 4) == [3, 2, 4, 1]
  assert kClosestValues([100, 200, 300, 400], 250, 2) == [200, 300]
output: def kClosestValues(lst, x, k):
      return sorted(lst, key=lambda num: abs(num - x))[:k]