anchor.diff:  resource_exists(_) -> 'true'.
   resource_exists(?CARRIERS,_) -> 'true';
   resource_exists(?MODB,_) -> 'true'.
  -resource_exists(?CARRIERS,_,?ATTACHMENT) -> 'true';
  +resource_exists(?CARRIERS,_,_) -> 'true';
   resource_exists(?MODB,_,?ATTACHMENT) -> 'true'.
   
   -spec content_types_provided(cb_context:context()) -> cb_context:context().
  
positive.code:             AccountId = cb_context:account_id(Context),
              <<"carrier.", (kz_util:to_binary(Id))/binary, ".", AccountId/binary>>
      end.
  
negative.code: validate_onbill(Context, ?CARRIERS, Id, ?HTTP_POST) ->
      save_onbill(build_carrier_doc_id(Id, Context), Context).
  
  validate_onbill(Context,?CARRIERS, Id, AttachmentId, ?HTTP_GET) ->
      load_carrier_attachment(Context, build_carrier_doc_id(Id, Context), <<Id/binary, "_", AttachmentId/binary, ".tpl">>);
  validate_onbill(Context,?MODB, Id, ?ATTACHMENT, ?HTTP_GET) ->
      load_modb_attachment(Context, Id).
  
  