func_code: def swap_unique_keys_values(d):
      unique = {}
      new_d = {}
      for key in d:
          if d[key] not in unique:
              unique[d[key]] = 0
          unique[d[key]] = unique[d[key]] + 1
      for key in d:
          if unique[d[key]] == 1:
              new_d[d[key]] = key
      return new_d