input: 
  def count_even_numbers(numbers: List[int]) -> int:
      """ Count the number of even numbers in a given list of integers.
      >>> count_even_numbers([1, 2, 3, 4, 5])
      2
      >>> count_even_numbers([2, 4, 6, 8, 10])
      5
      """
      return len([x for x in numbers if x % 2 == 0])
  
output:     count = 0
      for num in numbers:
          if num % 2 == 0:
              count += 1
      return count