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: keypair.go
    path of file: ./repos/kubelogin/integration_test/keypair
    
    the code of the file until where you have to start completion: package keypair

import (
	"crypto/tls"
	"crypto/x509"
	"encoding/base64"
	"io"
	"os"
	"strings"
)

// KeyPair represents a pair of certificate and key.
type KeyPair struct {
	CertPath     string
	KeyPath      string
	CACertPath
    
func readAsBase64(name string) string {
	f, err := os.Open(name)
	if err != nil {
		panic(err)
	}
	defer f.Close()
	var s strings.Builder
	e := base64.NewEncoder(base64.StdEncoding, &s)
	if _, err := io.Copy(e, f); err != nil {
		panic(err)
	}
	if err := e.Close(); err != nil {
		panic(err)
	}
	return s.String()
}