input: from typing import List
  
  def countEvenNum(list: List[int]) -> int:
      """ Count the number of even numbers in a given list.
      >>> countEvenNum([1, 2, 3, 4, 5])
      2
      >>> countEvenNum([0, 2, 4, 6, 8])
      5
      >>> countEvenNum([1, 3, 5, 7, 9])
      0
      """
      return len([x for x in list if x % 2 == 0])
output:     count = 0
      for num in list:
          if num % 2 == 0:
              count += 1
      return count