code: def signal_handler_mapping(self):
      
      # Could use an enum here, but we never end up doing any matching on the specific signal value,
      # instead just iterating over the registered signals to set handlers, so a dict is probably
      # better.
      return {
        signal.SIGINT: self.handle_sigint,
        signal.SIGQUIT: self.handle_sigquit,
        signal.SIGTERM: self.handle_sigterm,
      }
docs: A dict mapping (signal number) -> (a method handling the signal).