input: Write a python function to filter numbers greater than or equal to 3.
  assert filter_list([1, 2, 3, 4, 5]) == [3, 4, 5]
  assert filter_list([0, 2, 5, 7, 9]) == [5, 7, 9]
  assert filter_list([4, 3, 2, 1, 0]) == [4, 3]
output: def filter_list(lst):
      return [x for x in lst if x >= 3]