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

import (
	"bytes"
	"fmt"
	"io"
	"os"
	"sort"
	"strings"

	"github.com/spf13/pflag"
)

// Annotations for Bash completion.
const (
	BashCompFilenameExt     = "cobra_annotation_bash_completion_filename_extensions"
	BashCompCustom          = "cobra_annotation_bash_completion_custom"
	BashCompOneRequiredFlag = "cobra_annotation_
    
func prepareCustomAnnotationsForFlags(cmd *Command) {
	flagCompletionMutex.RLock()
	defer flagCompletionMutex.RUnlock()
	for flag := range flagCompletionFunctions {
		// Make sure the completion script calls the __*_go_custom_completion function for
		// every registered flag.  We need to do this here (and not when the flag was registered
		// for completion) so that we can know the root command name for the prefix
		// of __<prefix>_go_custom_completion
		if flag.Annotations == nil {
			flag.Annotations = map[string][]string{}
		}
		flag.Annotations[BashCompCustom] = []string{fmt.Sprintf("__%[1]s_handle_go_custom_completion", cmd.Root().Name())}
	}
}