input: Write a python function to classify numbers as odd or even.
  assert classify_odd_even([1, 2, 3, 4, 5]) == ['odd', 'even', 'odd', 'even', 'odd']
  assert classify_odd_even([10, 15, 20, 25, 30]) == ['even', 'odd', 'even', 'odd', 'even']
  assert classify_odd_even([0, 7, 8, 19, 22]) == ['even', 'odd', 'even', 'odd', 'even']
output: def classify_odd_even(numbers):
      return ['odd' if num % 2 != 0 else 'even' for num in numbers]