anchor.diff:  flow_rules([{_, _Endpoint, _}], _Graph, FlowRules, _Endpoint1, _Endpoint2) ->
       %% Nothing more to do.
       FlowRules;
  -flow_rules([{_, of_port, _}, connected_to | [{_, of_port, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
  +flow_rules([{_, of_port, _}, bound_to | [{_, of_port, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
       flow_rules(Tail, Graph, FlowRules, Endpoint1, Endpoint2);
  -flow_rules([{_, of_port, _}, connected_to | [{_, _Endpoint, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
  +flow_rules([{_, of_port, _}, bound_to | [{_, _Endpoint, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
       flow_rules(Tail, Graph, FlowRules, Endpoint1, Endpoint2);
  -flow_rules([{_, _Endpoint, _}, connected_to | [{_, of_port, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
  +flow_rules([{_, _Endpoint, _}, bound_to | [{_, of_port, _} | _] = Tail], Graph, FlowRules, Endpoint1, Endpoint2) ->
       flow_rules(Tail, Graph, FlowRules, Endpoint1, Endpoint2);
   flow_rules([{Port1, of_port, _}, part_of, {SwitchId, of_switch, _SwitchMetadata},
   	    part_of | [{Port2, of_port, _} | _] = Tail], Graph, FlowRules,
  
positive.code: tap_points([{_, _Endpoint, _}]) ->
      %% Nothing more to do.
      [];
  tap_points([{_, of_port, _}, connected_to | [{_, of_port, _} | _] = Tail]) ->
      tap_points(Tail);
  tap_points([{_, of_port, _}, connected_to | [{_, _Endpoint, _} | _] = Tail]) ->
      tap_points(Tail);
  tap_points([{_, _Endpoint, _}, connected_to | [{_, of_port, _} | _] = Tail]) ->
      tap_points(Tail);
  tap_points([{Port1, of_port, _}, part_of, {SwitchId, of_switch, _SwitchMetadata},
                part_of | [{Port2, of_port, _} | _] = Tail]) ->
  
negative.code: bridge_points([{_, _Endpoint, _}]) ->
      %% Nothing more to do.
      [];
  bridge_points([{_, of_port, _}, bound_to | [{_, of_port, _} | _] = Tail]) ->
      bridge_points(Tail);
  bridge_points([{_, of_port, _}, bound_to | [{_, _Endpoint, _} | _] = Tail]) ->
      bridge_points(Tail);
  bridge_points([{_, _Endpoint, _}, bound_to | [{_, of_port, _} | _] = Tail]) ->
      bridge_points(Tail);
  bridge_points([{Port1, of_port, _}, part_of, {SwitchId, of_switch, _SwitchMetadata},
                part_of | [{Port2, of_port, _} | _] = Tail]) ->
  