docs: def addHost(self, name=None):
          '''
          Add a new host node to the topology.
          '''
          if name is None:
              while True:
                  name = 'h' + str(self.__hnum)
                  self.__hnum += 1
                  if name not in self.__nxgraph:
                      break
          self.__addNode(name, Host)
          return name