code: def restoreState(self):
          
          if os.path.exists(self._stateFile):
              try:
                  fp = open(self._stateFile,  'r')
                  stateObj = pickle.load(fp)
              except:
                  raise IOError("Failure in reading plugin state from file: %s" 
                                % self._stateFile)
              return stateObj
          return None
docs: Utility method to restore plugin state from persistent storage to 
          permit access to previous plugin state.
          
          @return: Object that stores plugin state.