我有以下一段关于使用user-defined format 的代码，请好心人看看为何运行不通， 如何修改？ 先谢谢了。
libname Mylib 'my location';
proc format lib=Mylib;
value $itemfmt 'C'='Cassette' 'R'='Radio'  'T'='Television';
run;  

data sasuser.orders;
infile aug99dat;
input ID 3. @5 Date date7. Item $13 Quantity 15-17 Price 19-24 TotalCost 26-32;
format date date9.
item $itemfmt.
totalcost dollar9.2;
run;
NOTE: Format $ITEMFMT is already on the library.
NOTE: Format $ITEMFMT has been written to MYLIB.FORMATS.
2349 item $itemfmt.
---------48
ERROR 48-59: The format $ITEMFMT was not found or could not be loaded.