anchor.diff:  %%%===================================================================
   parse_opts(Props) ->
       Srv = case proplists:get_value(service, Props) of
  -	      undefined -> throw({error, {missing_opt, service}});
  -	      Str -> list_to_binary(Str)
  -	  end,
  +              undefined -> throw({error, {missing_opt, service}});
  +              Str -> list_to_binary(Str)
  +          end,
       Opts = case proplists:get_value(opts, Props) of
  -	       undefined -> [];
  -	       V -> V
  -	   end,
  +               undefined -> [];
  +               V -> V
  +           end,
       {Srv, Opts}.
   
   
   connect_backend(Service, Opts) ->
       case dbus_bus_connection:connect(session) of
  -	{ok, Bus} ->
  -	    ?info("Initializing backend service: ~s~n", [Service]),
  -	    case dbus_proxy:start_link(Bus, Service) of
  -		{ok, Backend} -> 
  -		    State = #state{conn=Bus, proxy=Backend},
  -		    init_service(State, Opts);
  -		{error, _} = Err -> Err
  -	    end;
  -	{error, _} = Err -> Err
  +        {ok, Bus} ->
  +            ?info("Initializing backend service: ~s~n", [Service]),
  +            case dbus_proxy:start_link(Bus, Service) of
  +                {ok, Backend} -> 
  +                    State = #state{conn=Bus, proxy=Backend},
  +                    init_service(State, Opts);
  +                {error, _} = Err -> Err
  +            end;
  +        {error, _} = Err -> Err
       end.
   
   
   init_service(#state{proxy=Backend}=State, Opts) ->
       case dbus_proxy:call(Backend, ?IFACE_BACKEND, <<"Init">>, [Opts]) of
  -	ok ->
  -	    ?debug("Initialization ok...", []),
  -	    Schema = dbus_properties_proxy:get(Backend, ?IFACE_BACKEND, 'schema'),
  -	    {ok, [Schema], 
  -	     State#state{
  -	       i_mixin=dbus_proxy:has_interface(Backend, ?IFACE_BACKEND_MIXIN),
  -	       i_action=dbus_proxy:has_interface(Backend, ?IFACE_BACKEND_ACTION)}};
  -	{error, {Code, Err}} ->
  -	    ?debug("Error initializing: ~n"
  -		   "Code=~s~n"
  -		   "Reason=~n~s~n", [Code, Err]),
  -	    {error, Err}
  -    end.
  +        ok ->
  +            ?debug("Initialization ok...", []),
  +            Schema = dbus_properties_proxy:get(Backend, ?IFACE_BACKEND, 'schema'),
  +            {ok, [Schema], 
  +             State#state{
  +               i_mixin=dbus_proxy:has_interface(Backend, ?IFACE_BACKEND_MIXIN),
  +               i_action=dbus_proxy:has_interface(Backend, ?IFACE_BACKEND_ACTION)}};
  +        {error, {Code, Err}} ->
  +            ?debug("Error initializing: ~n"
  +                   "Code=~s~n"
  +                   "Reason=~n~s~n", [Code, Err]),
  +            {error, Err}
  +    end.
  
positive.code: 
  %% occi_backend callbacks
  -export([init/1,
  	 terminate/1]).
  -export([update/2,
  	 save/2,
  	 delete/2,
  	 find/2,
  	 load/3,
  	 action/3]).
  
  -record(state, {conn      :: dbus_connection(),
  		proxy     :: dbus_proxy(),
  		i_mixin   :: boolean(),
  		i_action  :: boolean()}).
  
  %%%===================================================================
  %%% occi_backend callbacks
  %%%===================================================================
  init(#occi_backend{opts=Props}) ->
      try parse_opts(Props) of
  	{Service, Opts} -> connect_backend(Service, Opts)
      catch throw:Err -> {error, Err}
      end.
  
  
  terminate(#state{proxy=Backend}) ->
      case dbus_proxy:call(Backend, ?IFACE_BACKEND, <<"Terminate">>, []) of
  	_ -> ok
      end.
  
  
  
negative.code: 
  
  action(#state{i_action=false}=State, #uri{}, #occi_action{}) ->
                                                  % TODO: handle this in occi_store: do not query backend in case it does not 
                                                  % support and return sthig like 403
      {ok, State};
  
  action(#state{proxy=Backend}=State, #uri{}=Id, #occi_action{}=Action) ->
      ?info("[~p] action(~p, ~p)~n", [?MODULE, Id, Action]),
      EntityId = occi_uri:to_binary(Id), 
      ActionId = occi_cid:to_binary(occi_action:id(Action)),
      Attrs = [ { occi_attribute:get_id(A), occi_attribute:get_value(A)} 
                || A <- occi_action:get_attr_list(Action) ],
      case dbus_proxy:call(Backend, ?IFACE_BACKEND, <<"Action">>, [EntityId, ActionId, Attrs]) of
          ok ->
              {ok, State};
          {error, Err} ->
              {{error, Err}, State}
      end.
  
  %%%===================================================================
  