You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: jobobject.go
    path of file: ./repos/podman/vendor/github.com/Microsoft/hcsshim/internal/jobobject
    
    the code of the file until where you have to start completion: //go:build windows

package jobobject

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"sync"
	"sync/atomic"
	"unsafe"

	"github.com/Microsoft/hcsshim/internal/queue"
	"github.com/Microsoft/hcsshim/internal/winapi"
	"golang.org/x/sys/windows"
)

// JobObject is a high level
    
func (job *JobObject) Assign(pid uint32) error {
	job.handleLock.RLock()
	defer job.handleLock.RUnlock()

	if job.handle == 0 {
		return ErrAlreadyClosed
	}

	if pid == 0 {
		return errors.New("invalid pid: 0")
	}
	hProc, err := windows.OpenProcess(winapi.PROCESS_ALL_ACCESS, true, pid)
	if err != nil {
		return err
	}
	defer windows.Close(hProc)
	return windows.AssignProcessToJobObject(job.handle, hProc)
}