input: Write a function to generate a new list containing the square of all numbers in a list.
  assert generate_squares([1, 2, 3, 4, 5]) == [1, 4, 9, 16, 25]
  assert generate_squares([0, -1, -2, -3, 6]) == [0, 1, 4, 9, 36]
  assert generate_squares([10, 100, 1000]) == [100, 10000, 1000000]
output: def generate_squares(numbers):
      return [x ** 2 for x in numbers]