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: logger.go
    path of file: ./repos/goka
    
    the code of the file until where you have to start completion: package goka

import (
	"fmt"
	"log"
	"os"
	"strin
    
func (s *std) StackPrefix(prefix string) logger {
	var prefPath []string
	// append existing path
	prefPath = append(prefPath, s.prefixPath...)

	// if new is not empty, append to path
	if prefix != "" {
		prefPath = append(prefPath, prefix)
	}

	// make new prefix
	newPrefix := strings.Join(prefPath, " > ")
	if newPrefix != "" {
		newPrefix = "[" + newPrefix + "] "
	}

	return &std{
		log:        s.log,
		prefixPath: prefPath,
		prefix:     newPrefix,
		debug:      s.debug,
	}
}