题目内容：

lingo 错误的1017
我在model后面打过：
model:
sets:
para/1..3/:y;
warehouses/wh1..wh3/:capacity;
vendors/v1..v4/:demand;
links(warehouses,vendors):cost,volume;
endsets
目标函数;
min=@sum(links:cost*volume)+91y(1)+70y(2)+24y(3);
@for(para:@bin(y));
需求约束;
@for(vendors(J):
@sum(warehouses(I):volume(I,J))=demand(J));
产量约束;
@for(warehouses(I):
@sum(vendors(J):volume(I,J))