input: Write a python function to filter numbers not divisible by 3 from a list.
  assert filter_div_by_3([9, 8, 10, 27, 12, 15]) == [8, 10]
  assert filter_div_by_3([3, 6, 9, 12, 15, 18]) == []
  assert filter_div_by_3([4, 5, 7, 11, 14]) == [4, 5, 7, 11, 14]
output: def filter_div_by_3(numbers):
      return [num for num in numbers if num % 3 != 0]