code: def getSwapStats(self, dev):
          
          if self._swapList is None:
              self._initSwapInfo()
          if dev in self._swapList:
              return self.getDevStats(dev)
          else:
              return None
docs: Returns I/O stats for swap partition.
          
          @param dev: Device name for swap partition.
          @return: Dict of stats.