input: Write a python function to classify numbers as even or odd.
  assert classify_numbers([4, 7, 9, 11, 12]) == ["4 is even", "7 is odd", "9 is odd", "11 is odd", "12 is even"]
  assert classify_numbers([2, 3, 5, 8, 10]) == ["2 is even", "3 is odd", "5 is odd", "8 is even", "10 is even"]
  assert classify_numbers([1, 2, 3, 4, 5]) == ["1 is odd", "2 is even", "3 is odd", "4 is even", "5 is odd"]
output: def classify_numbers(numbers):
      result = []
      for num in numbers:
          if num % 2 == 0:
              result.append(f"{num} is even")
          else:
              result.append(f"{num} is odd")
      return result