input: def filter_even_numbers(numbers):
      """Filters out all the even numbers from a given list and returns a list of even numbers.
      Example:
      >>> filter_even_numbers([3, 4, 5, 6, 7])
      [4, 6]
      """
output:     even_numbers = [num for num in numbers if num % 2 == 0]
      return even_numbers