code: def member_create(self, params, member_id):
          
          member_config = params.get('rsParams', {})
          server_id = params.pop('server_id', None)
          version = params.pop('version', self._version)
          proc_params = {'replSet': self.repl_id}
          proc_params.update(params.get('procParams', {}))
          if self.enable_ipv6:
              enable_ipv6_single(proc_params)
          # Make sure that auth isn't set the first time we start the servers.
          proc_params = self._strip_auth(proc_params)
  
          # Don't pass in auth_key the first time we start the servers.
          server_id = self._servers.create(
              name='mongod',
              procParams=proc_params,
              sslParams=self.sslParams,
              version=version,
              server_id=server_id
          )
          member_config.update({"_id": member_id,
                                "host": self._servers.hostname(server_id)})
          return member_config
docs: start new mongod instances as part of replica set
          Args:
              params - member params
              member_id - member index
  
          return member config