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: completions.go
    path of file: ./repos/sealer/vendor/github.com/spf13/cobra
    
    the code of the file until where you have to start completion: package cobra

import (
	"fmt"
	"os"
	"strings"
	"sync"

	"github.com/spf13/pflag"
)

const (
	// ShellCompRequestCmd is the name of the hidden command that is used to request
	// completion results from the program.  It is used by the shell completion scripts.
	ShellCompRequestCmd = "__complete"
	// ShellCompNoDescRequestCmd is the name of the hidden command that is used to request
	// completion results without their description.  It is used by the shell completion scripts.
	ShellCompNoDescRequestCmd = "__completeNoDesc"
)

// Global map of flag completion functions. Make sure to use flagCompletionMutex before you try to read and write from it.
var flagCompletionFunctions = map[*pflag.Flag]func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective){}

// lock for 
    
func getFlagNameCompletions(flag *pflag.Flag, toComplete string) []string {
	if nonCompletableFlag(flag) {
		return []string{}
	}

	var completions []string
	flagName := "--" + flag.Name
	if strings.HasPrefix(flagName, toComplete) {
		// Flag without the =
		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))

		// Why suggest both long forms: --flag and --flag= ?
		// This forces the user to *always* have to type either an = or a space after the flag name.
		// Let's be nice and avoid making users have to do that.
		// Since boolean flags and shortname flags don't show the = form, let's go that route and never show it.
		// The = form will still work, we just won't suggest it.
		// This also makes the list of suggested flags shorter as we avoid all the = forms.
		//
		// if len(flag.NoOptDefVal) == 0 {
		// 	// Flag requires a value, so it can be suffixed with =
		// 	flagName += "="
		// 	completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
		// }
	}

	flagName = "-" + flag.Shorthand
	if len(flag.Shorthand) > 0 && strings.HasPrefix(flagName, toComplete) {
		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
	}

	return completions
}