input: from typing import List
  
  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([0, 2, 4, 6, 8, 10])
      6
      >>> count_even_numbers([1, 3, 5, 7, 9])
      0
      """
      return len([x for x in numbers if x % 2 == 0])
output:     return len([x for x in numbers if x % 2 == 0])