code: def get_cluster_nodes(self):
          
          if not hasattr(self, '_cluster_nodes_cache'):
              server, port = self._servers[0].split(':')
              try:
                  self._cluster_nodes_cache = (
                      get_cluster_info(server, port,
                                       self._ignore_cluster_errors)['nodes'])
              except (socket.gaierror, socket.timeout) as err:
                  raise Exception('Cannot connect to cluster {0} ({1})'.format(
                      self._servers[0], err
                  ))
          return self._cluster_nodes_cache
docs: return list with all nodes in cluster