<s> from neutron . services . auto_allocate import db <EOL> class Plugin ( db . AutoAllocatedTopologyMixin ) : <EOL> _instance = None <EOL> supported_extension_aliases = [ "<STR_LIT>" ] <EOL> @ classmethod <EOL> def get_instance ( cls ) : <EOL> if cls . _instance is None : <EOL> cls . _instance = cls ( ) <EOL> return cls . _instance <EOL> def get_plugin_description ( self ) : <EOL> return "<STR_LIT>" <EOL> def get_plugin_type ( self ) : <EOL> return "<STR_LIT>" </s>
