input: Write a python function to sum the squares of a list of numbers.
  assert sum_of_squares([1, 2, 3, 4, 5]) == 55
  assert sum_of_squares([10, 20, 30]) == 1400
  assert sum_of_squares([0, -1, -2, -3]) == 14
output: def sum_of_squares(numbers):
      return sum(x**2 for x in numbers)