code: def _construct_config(self, basedir, port, name=None, isreplset=False):
          
          if isreplset:
              return self._construct_replset(basedir=basedir, portstart=port,
                                             name=name,
                                             num_nodes=list(range(
                                                 self.args['config'])),
                                             arbiter=False, extra='--configsvr')
          else:
              datapath = self._create_paths(basedir, name)
              self._construct_mongod(os.path.join(datapath, 'db'),
                                     os.path.join(datapath, 'mongod.log'),
                                     port, replset=None, extra='--configsvr')
docs: Construct command line strings for a config server.