input: Write a python function to filter positive numbers from a list.
  assert filter_positive([-10, -5, 0, 5, 10]) == [5, 10]
  assert filter_positive([1, 2, 3, -1, -2, -3]) == [1, 2, 3]
  assert filter_positive([-1, -2, -3, -4]) == []
  assert filter_positive([0, 0, 0, 0]) == []
output: def filter_positive(numbers):
      return [num for num in numbers if num > 0]