code: def UpdateChainAndProcess(self, parser_mediator, registry_key, **kwargs):
      
      parser_mediator.AppendToParserChain(self)
      try:
        self.Process(parser_mediator, registry_key, **kwargs)
      finally:
        parser_mediator.PopFromParserChain()
docs: Updates the parser chain and processes a Windows Registry key or value.
  
      Args:
        parser_mediator (ParserMediator): mediates interactions between parsers
            and other components, such as storage and dfvfs.
        registry_key (dfwinreg.WinRegistryKey): Windows Registry key.
  
      Raises:
        ValueError: If the Windows Registry key is not set.