Get the current coordinator

        Returns: the current coordinator id or None if it is unknown

def coordinator(self):
        """Get the current coordinator

        Returns: the current coordinator id or None if it is unknown
        """
        if self.coordinator_id is None:
            return None
        elif self._client.is_disconnected(self.coordinator_id):
            self.coordinator_dead('Node Disconnected')
            return None
        else:
            return self.coordinator_id