input: Write a function to filter an array by a given criteria. The function should take in an array and a criteria function, then return a list of elements that satisfy the criteria. If the given array is empty, the function should return an empty list.
  assert filter_array([1, 2, 5, 10, 15, 20, 25, 30], lambda x: x % 5 == 0) == [5, 10, 15, 20, 25, 30]
  assert filter_array([1, 2, 3, 4, 6, 7, 8, 9], lambda x: x % 5 == 0) == []
  assert filter_array([], lambda x: x % 5 == 0) == []
output: def filter_array(arr, criteria):
      return [x for x in arr if criteria(x)]