input: Write a function to calculate the sum of squares of all numbers in the given array.
  
  assert sum_squares([2, 3, 4])==29
  assert sum_squares([0, 0, 0])==0
  assert sum_squares([1, 1, 1])==3
  assert sum_squares([5, 5, 5])==75
  assert sum_squares([])==0
output: def sum_squares(arr):
      return sum(x ** 2 for x in arr)