input: Write a function to classify numbers in a list as 'even' or 'odd'.
  assert classifier([1, 2, 3, 4, 5, 6]) == ['odd', 'even', 'odd', 'even', 'odd', 'even']
  assert classifier([10, 15, 22, 33]) == ['even', 'odd', 'even', 'odd']
  assert classifier([0, 13, 26, 39, 52]) == ['even', 'odd', 'even', 'odd', 'even']
output: def classifier(numbers):
      return ['even' if num % 2 == 0 else 'odd' for num in numbers]