迈克尔逊对不具有可比性

当我尝试键入以下迈克尔逊脚本时,出现输入错误.

 parameter unit;
storage (big_map (pair string address) (list timestamp));
code {CDR; NIL operation; PAIR};
 

 Ill formed type.
At line 2 characters 17 to 37,
comparable type expected.Type pair string address is not comparable.
 

根据米歇尔森引用,键入pair ty1 ty2,address和string是可比较的.我想念什么吗?有什么方法可以解决这个问题?

When I try to type the following Michelson script, I get a type error.

parameter unit;
storage (big_map (pair string address) (list timestamp));
code {CDR; NIL operation; PAIR};

Ill formed type.
At line 2 characters 17 to 37,
comparable type expected.Type pair string address is not comparable.

According to the Michelson reference, types pair ty1 ty2, address, and string are comparable. Am I missing something? Is there are way to circumvent this issue?