func_code: def swap_unique_keys_values(d):
      swap1 = {}
      swap2 = {}
      swapsorted1 = sorted(list(d.items()), reverse=True)
      for k, v in swapsorted1:
          if v not in swap1:
              swap1[v] = k
          else:
              swap1[v] = 'N'
      swapsorted2 = sorted(list(swap1.items()), reverse=True)
      for k, v in swapsorted2:
          if v != 'N':
              swap2[k] = v
      return swap2