input: Write a function to calculate the sum of squares of all numbers provided in an array of integers. If the given array is empty then return 0.
  assert sum_squares([2, 3, 4])==29
  assert sum_squares([1, 2, 3, 4, 5])==55
  assert sum_squares([0])==0
  assert sum_squares([])==0
  assert sum_squares([-1, -2, -3])==14
output: def sum_squares(arr):
      return sum(x**2 for x in arr)