def restoreState(self):
if os.path.exists(self._stateFile):<EOL><INDENT>try:<EOL><INDENT>fp = open(self._stateFile,  '<STR_LIT:r>')<EOL>stateObj = pickle.load(fp)<EOL><DEDENT>except:<EOL><INDENT>raise IOError("<STR_LIT>" <EOL>% self._stateFile)<EOL><DEDENT>return stateObj<EOL><DEDENT>return None<EOL>
Utility method to restore plugin state from persistent storage to 
        permit access to previous plugin state.

        @return: Object that stores plugin state.