code: def set_node(self, host, port, server_type=None):
          
          node_name = "{0}:{1}".format(host, port)
          node = {
              'host': host,
              'port': port,
              'name': node_name,
              'server_type': server_type
          }
          self.nodes[node_name] = node
          return node
docs: Update data for a node.