anchor.diff:  			case global:whereis_name(Etag) of
   				undefined ->
   					{error, 412};
  -				PageServer ->
  -					case ocs_rest:range(Range) of
  -						{error, _} ->
   							{error, 400};
   						{ok, {Start, End}} ->
   							query_page(Codec, PageServer, Etag, Query, Filters, Start, End)
  
positive.code: 		case ocs:add_offer(offer(mochijson:decode(ReqData))) of
  			{ok, ProductOffering} ->
  				ProductOffering;
  			{error, Reason} ->
  				throw(Reason)
  		end
  
negative.code: inventory(ProductInstance) ->
  	{struct, inventory(record_info(fields, product), ProductInstance, [])}.
  %% @hidden
  inventory([{"id", Id} | T], Acc) when is_list(Id) ->
  	inventory(T, Acc#product{id = Id});
  inventory([{"characteristic", Chars} | T], Acc) ->
  	inventory(T, Acc#product{characteristics = instance_chars(Chars)});
  inventory([{"productOffering", {struct, Offer}} | T], Acc) ->
  