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: completion.go
    path of file: ./repos/sealer/vendor/github.com/containers/buildah/pkg/completion
    
    the code of the file until where you have to start completion: package completion

import (
	"strings"

	"github.com/spf13/cobra"
)

/* Autocomplete Functions for cobra ValidArgsFunction */

// AutocompleteNamespaceFlag - Autocomplete the userns flag.
// -> host, private, container, ns:[path], [path]
func AutocompleteNamespaceFlag(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
	var completions []string
	// If we don't filter on "toComplete", zsh and fish will not do file completion

    
func AutocompleteNamespaceFlag(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
	var completions []string
	// If we don't filter on "toComplete", zsh and fish will not do file completion
	// even if the prefix typed by the user does not match the returned completions
	for _, comp := range []string{"host", "private", "container", "ns:"} {
		if strings.HasPrefix(comp, toComplete) {
			completions = append(completions, comp)
		}
	}
	return completions, cobra.ShellCompDirectiveDefault
}