anchor.diff:  -export([
   	new_dt/1,
   	update_dt/3,
  +	update_groups_dt/3,
   	group_rawdt/2,
   	find_group_rawdt/2,
   	fold_groups_dt/3,
  
positive.code: -export([
  	put_groups/4,
  	put_groups/5,
  	remove_groups/4,
  	update_groups/4,
  	update_groups/5,
  	find/3,
  
negative.code: %% =============================================================================
  %% Internal functions
  %% =============================================================================
  
  -spec put_groups_([{binary(), riakacl_group:group()}], riakacl_group:group()) -> riakacl_group:group().
  put_groups_(Groups, Gs) ->
  	lists:foldl(
  		fun({Name, Group}, Acc) ->
  			riakc_map:update({Name, map}, fun(_) -> Group end, Acc)
  		end, Gs, Groups).
  
  -spec remove_groups_([binary()], riakacl_group:group()) -> riakacl_group:group().
  remove_groups_(Names, Gs) ->
  	lists:foldl(
  		fun(Name, Acc) ->
  			riakc_map:erase({Name, map}, Acc)
  		end, Gs, Names).
  
  -spec cleanup_groups_dt_(riakc_map:crdt_map(), non_neg_integer()) -> riakc_map:crdt_map().
  cleanup_groups_dt_(Gs, Time) ->
  