为什么我的crypt包会给我无效的魔术前缀错误？

Question

I have the following code:

import "github.com/kless/osutil/user/crypt/sha512_crypt"
c := sha512_crypt.New()
hash, err := c.Generate([]byte("enter-new-password"), []byte("$2a$09$f5561d2634fb28a969f2dO8QeQ70f4bjCnF/.GvPpjj.8jgmtzZP2"))
if err != nil {
    panic(err)
}

And it produced the following error

http: panic serving 192.168.0.16:56730: invalid magic prefix

Why does this happen and how do I resolve it?