code: def delete_router_references(self, snet, address=None, dnets=None):
          
          if _debug: NetworkServiceAccessPoint._debug("delete_router_references %r %r %r", snet, address, dnets)
  
          # see if we have an adapter for the snet
          if snet not in self.adapters:
              raise RuntimeError("no adapter for network: %d" % (snet,))
  
          # pass this along to the cache
          self.router_info_cache.delete_router_info(snet, address, dnets)
docs: Delete references to routers/networks.