code: def clear_shell(self):
          
          with self._lock:
              # Clear the flag
              self._shell_event.clear()
  
              # Clear the readline completer
              if readline is not None:
                  readline.set_completer(None)
                  del self._readline_matches[:]
  
              if self._shell_ref is not None:
                  # Release the service
                  self._context.unget_service(self._shell_ref)
  
              self._shell_ref = None
              self._shell = None
docs: Unbinds the active shell service