input: Write a python function to square a list of numbers.
  assert square_list([1, 2, 3, 4, 5]) == [1, 4, 9, 16, 25]
  assert square_list([10, 20, 30]) == [100, 400, 900]
  assert square_list([0, -1, -2]) == [0, 1, 4]
output: def square_list(numbers):
      return [x ** 2 for x in numbers]