input: def sum_squares(lst):
      """
      This function processes a list of integers. It squares the element if located at an index that is a multiple of 3, and cubes it if the index is a multiple of 4 but not 3. Entries with indexes that are neither multiples of 3 nor 4 remain unchanged. The function returns the sum of all processed entries.
      
      Examples:
      For lst = [1,2,3] the result should be 6
      For lst = [] the result should be 0
      For lst = [-1,-5,2,-1,-5] the result should be -126
      """
output:     total = 0
      for i, val in enumerate(lst):
          if i % 3 == 0:
              total += val * val
          elif i % 4 == 0:
              total += val * val * val
          else:
              total += val
      return total