code: def _mark_master_dead(self, master):
          '''
          Mark a master as dead. This will start the sign-in routine
          '''
          # if its connected, mark it dead
          if self._syndics[master].done():
              syndic = self._syndics[master].result()  # pylint: disable=no-member
              self._syndics[master] = syndic.reconnect()
          else:
              # TODO: debug?
              log.info(
                  'Attempting to mark %s as dead, although it is already '
                  'marked dead', master
              f _mark_master_dead(self, master):
          '''
          Mark a master as dead. This will start the sign-in routine
          '''
          # if its connected, mark it dead
          if self._syndics[master].done():
              syndic = self._syndics[master].result()  # pylint: disable=no-member
              self._syndics[master] = syndic.reconnect()
          else:
              # TODO: debug?
              log.info(
                  'Attempting to mark %s as dead, although it is already '
                  'marked dead', master
              )
docs: Mark a master as dead. This will start the sign-in routine