@unique decorator在python中做什么？

Question

我最近从一个stackoverflow question中看到了这段代码：

@unique
class NetlistKind(IntEnum):
  Unknown = 0
  LatticeNetlist = 1
  QuartusNetlist = 2
  XSTNetlist = 4
  CoreGenNetlist = 8
  All = 15

def __contains__(self, item):
  return  (self.value & item.value) == item.value

@unique修饰符做什么，它在这个代码片段中的用途是什么？在

Answer 1

来自documentation（谢谢@HFBrowning）：

[@unique is] a class decorator specifically for enumerations. It searches an enumeration’s members gathering any aliases it finds; if any are found ValueError is raised with the details

基本上，如果存在任何重复的枚举值，则会引发错误。在

这个代码

 class Mistake(Enum):
     ONE = 1
     TWO = 2
     THREE = 3
     FOUR = 3

产生此错误：

^{pr2}$