How to delete the go language map dictionary

package main
import "fmt"
func main(){
    var pc map[string] string
    pc = make(map[string] string)
pc["qingdao"] = "Qingdao"
pc["jinan"] = "Jinan"
pc["yantai"] = "Yantai"
    delete(pc,"qingdao")
    qingdao,ok := pc["qingdao"]
    if ok{
        (qingdao)  
    }else{
("Element does not exist")
    }
}