docs: def _handle_signals(self, signum, frame):
          """Handler for all signals.
  
          This method must be used to handle all signals for the process. It is
          responsible for runnin the appropriate signal handlers registered with
          the 'handle' method unless they are shutdown signals. Shutdown signals
          must trigger the 'shutdown' method.
          """
          if signum in self.kill_signals:
  
              return self.shutdown(signum)
  
          for handler in self._handlers[signum]:
  
              handler()