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