input: Write a function to print even numbers from a list.
  assert print_even_numbers([1, 2, 3, 4, 5, 6, 7, 8, 9])==[2, 4, 6, 8]
  assert print_even_numbers([10, 15, 20, 25])==[10, 20]
  assert print_even_numbers([11, 13, 17, 19])==[]
output: def print_even_numbers(lst):
      return [num for num in lst if num % 2 == 0]