code: def accept(self, origin, protocol):
          
          for factory in self.store.powerupsFor(IBoxReceiverFactory):
              # XXX What if there's a duplicate somewhere?
              if factory.protocol == protocol:
                  receiver = factory.getBoxReceiver()
                  route = self.router.bindRoute(receiver)
                  # This might be better implemented using a hook on the box.
                  # See Twisted ticket #3479.
                  self.reactor.callLater(0, route.connectTo, origin)
                  return {'route': route.localRouteName}
          raise ProtocolUnknown()
docs: Create a new route attached to a L{IBoxReceiver} created by the
          L{IBoxReceiverFactory} with the indicated protocol.
  
          @type origin: C{unicode}
          @param origin: The identifier of a route on the peer which will be
              associated with this connection.  Boxes sent back by the protocol
              which is created in this call will be sent back to this route.
  
          @type protocol: C{unicode}
          @param protocol: The name of the protocol to which to establish a
              connection.
  
          @raise ProtocolUnknown: If no factory can be found for the named
              protocol.
  
          @return: A newly created C{unicode} route identifier for this
              connection (as the value of a C{dict} with a C{'route'} key).