code: def mset(self, mapping):
          
          servers = {}
          for key, value in mapping.items():
              server_name = self.get_server_name(key)
              servers.setdefault(server_name, [])
              servers[server_name].append((key, value))
          for name, items in servers.items():
              self.connections[name].mset(dict(items))
          return True
docs: Sets each key in the ``mapping`` dict to its corresponding value