anchor.diff:  
   % exports for unit tests
   -export([check_rt_integrity/1
  +        , check_well_connectedness/1
           , get_random_key_from_generator/3
       ]).
   
  
positive.code:                 -> SpacingA =< SpacingB
              end, Spacings)
      ),
      entry_delete(entry_nodeid(FilterEntry), RT)
      .
  
  % @doc Delete an entry from the routing table
  
negative.code: % @doc Get the source node of a routing table
  -spec get_source_node(RT :: rt()) -> rt_entry().
  get_source_node(#rt_t{source=undefined}) -> erlang:error("routing table source unknown");
  get_source_node(#rt_t{source=NodeId, nodes=Nodes}) ->
      case Nodes =:= gb_trees:empty() of
              false ->
                  gb_trees:get(NodeId, Nodes);
              true  ->
                  exit(rt_broken_tree_empty)
      end.
  
  % @doc Set the source node of a routing table
  -spec set_source_node(SourceId :: key(), RT :: rt()) -> rt().
  