anchor.diff:  			  rbtree:delete(Value, vk_tree(Bush))}}
       end.
   
  +%% @doc Drop an item given by its value from a bush. Return new bush or false if no item found.
  +%% @spec take_v(Value, Bush) -> Bush | false
   take_v(Value, Bush) ->
       case lookup_v(Value, Bush) of
   	{} -> false;
  
positive.code: %% @author Oleg Smirnov <oleg.smirnov@gmail.com>
  %% @doc Bush data structure
  %% Basically, bush is a set of two RB-trees.
  %% First is indexed in a normal way. Second has keys swapped with values. 
  
  -module(bush).
  
  
negative.code: 	     rbtree:delete(Value, vk_tree(Bush))}
      end.
  
  %% @doc Drop an item given by its key from a bush. Return new bush or false if no item found.
  %% @spec take_k(Key, Bush) -> Bush | false
  take_k(Key, Bush) ->
      case lookup_k(Key, Bush) of
  	{} -> false;
  