def __init__(self, nopts=None, **opts):
        self.nopts = {} if nopts is None else nopts
        BaseTopo.__init__(self, **opts)

    # Override addHost so that constructor defaults to MiniNExT host
Extended Topo object:
dataset/ETHPy150Open USC-NSL/miniNExT/mininext/topo.py/Topo.__init__