Golnag killing port pid

package main

import (
        "fmt"
        "github.com/drael/GOnetstat"
        "os"
        "strconv"
        // "syscall"
        // "errors"
)

func main() {
        // listports()
        killPort(9999)
}

func stopServer(proc *os.Process) {
        err := proc.Kill()
        if err != nil {
                panic(err.Error())
        }
        proc.Release()
}

func killPID(pid int) {
        process, err := os.FindProcess(pid)
        if err != nil {
                panic(err.Error())
        }
        process.Signal(os.Interrupt)
}

func killPort(port int64) {
        d := GOnetstat.Tcp()
        for _, p := range d {
                if p.State == "LISTEN" && p.Port == port {
                        fmt.Printf("Killing port, pid, name %v %v %v\n", port, p.Pid, p.Name)
                        pid, err := strconv.Atoi(p.Pid)
                        if err != nil {
                                panic(err.Error())
                        }
                        killPID(pid)
                }
        }
}

func listPorts() {
        d := GOnetstat.Tcp()

        fmt.Printf("Proto %16s %20s %14s %14s %14s\n", "Local Adress", "Foregin Adress",
                "State", "Pid", "Program")

        for _, p := range d {
                if p.State == "LISTEN" {
                        fmt.Printf("foo")
                }

                if p.State == "LISTEN" {
                        ip_port := fmt.Sprintf("%v:%v", p.Ip, p.Port)
                        fip_port := fmt.Sprintf("%v:%v", p.ForeignIp, p.ForeignPort)
                        pid := fmt.Sprintf("%v", p.Pid)
                        program := fmt.Sprintf("%v", p.Name)
                        fmt.Printf("tcp %16v %20v %16v %14v %14v\n", ip_port, fip_port,
                                p.State, pid, program)
                }
        }
}