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: utils.go
    path of file: ./repos/yq/pkg/yqlib
    
    the code of the file until where you have to start completion: package yqlib

import (
	"bufio"
	"container/list"
	"errors"
	"fmt"
	"io"
	"os"
)

func readStream(filename string) (io.Reader, error) {
	var reader *bufio.Reader
	if filename == "-" {
		reader = bufio.NewReader(os.Stdin)
	} else {
		// ignore CWE-22 gosec issue - that's more targeted for http based apps that run in a public directory,
		// and ensuring that it's not possible to give a path to a file outside that director
    
func readStream(filename string) (io.Reader, error) {
	var reader *bufio.Reader
	if filename == "-" {
		reader = bufio.NewReader(os.Stdin)
	} else {
		// ignore CWE-22 gosec issue - that's more targeted for http based apps that run in a public directory,
		// and ensuring that it's not possible to give a path to a file outside that directory.
		file, err := os.Open(filename) // #nosec
		if err != nil {
			return nil, err
		}
		reader = bufio.NewReader(file)
	}
	return reader, nil

}