input: Write a python function to filter numbers divisible by three from a list using the is_divisible_by_three function.
  assert filter_divisible_by_three([1, 3, 4, 6, 9, 11, 12]) == [3, 6, 9, 12]
  assert filter_divisible_by_three([2, 5, 7, 8, 10, 13]) == []
  assert filter_divisible_by_three([3, 6, 15, 18, 21, 24]) == [3, 6, 15, 18, 21, 24]
output: def is_divisible_by_three(number):
      return number % 3 == 0
  
  def filter_divisible_by_three(numbers):
      return [num for num in numbers if is_divisible_by_three(num)]