func_code: def swap_unique_keys_values(d):
      new_dict = {}
      values_once = set(d.values())
      unique_values = []
      for n in values_once:
          if list(d.values()).count(n) == 1:
              unique_values.append(n)
      for k, v in list(d.items()):
          if v in unique_values:
              new_dict[v] = k
      return new_dict