I want to insert feed's value to myself‘s custom functions,but failed

My code part:

`

public static String Code(String token,String url,String test)
{
String authcode =toHex(encryptionHMACMD5(token.getBytes(),url));
return authcode;
}

def randomCode(token: String,url: String,name: String): Iterator[Map[String,String]] = {
Iterator.continually(Map(name → Code(token,url)))
}
object plateNumber{
val feeder = csv(“plateNumber.csv”).circular
val Exec = feed(feeder)
.feed(randomUuid(30,“id”))
.exec(.set(“token”,token))
.exec(.set(“apiKey”,api_key))
.exec(_.set(“kksmall_url”,plateNumberUrl))
.feed(time(“yyyy-MM-dd HH:mm:ss”,“imageTime”))
.feed(randomCode("${token}",plateNumberUrl,“newkey”))
.exec(http(“test”)
.post("/signalway/image/structurization.htm")
.body(ElFileBody(“plateNumber.json”)).asJSON
.check(status.is(200),
jsonPath("$.code").is(“0”)
)
)
}

`

randomCode("${token}",plateNumberUrl,“newkey”)

I print token value in Code ,the value is “${token}” ,but i want to token actually value