input: Write a python function to create a new list of squares of even numbers from a given list.
  assert get_even_squares([1, 2, 3, 4, 5, 6]) == [4, 16, 36]
  assert get_even_squares([10, 15, 20, 25, 30]) == [100, 400, 900]
  assert get_even_squares([7, 8, 9, 10, 11, 12]) == [64, 100, 144]
output: def get_even_squares(numbers):
      return [x ** 2 for x in numbers if x % 2 == 0]