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: cas.go
    path of file: ./repos/gitkube/vendor/github.com/peterbourgon/diskv/examples/content-addressable-store
    
    the code of the file until where you have to start completion: package main

import (
	"crypto/md5"
	"fmt"
	"io"

	"github.com/peterbourgon/diskv"
)

const transformBlockSize = 2 // grouping of chars per directory depth

func blockTransform(s string) []string {
	var (
		sliceSize = len(s) / transformBlockSize
		pathSlice = make([]string, sliceSize)
	)
	for i := 0; i < sliceSize; i++ {
		from, to := i*transformBlockSize, (i*transformBlockSize)+transformBlockSize
		pathSlice[i] = s[from:to]
	}
	return pathSlice
}

func main() {
	d := diskv.New(diskv.Options{
		BasePath:     "data",
		Transform:    blockTransform,
		CacheSizeMax: 1024 * 1024, // 1MB
	})

	for _, valueStr := range []string{
		"I am the very model of a modern Major-General",
		"I've informati
    
func main() {
	d := diskv.New(diskv.Options{
		BasePath:     "data",
		Transform:    blockTransform,
		CacheSizeMax: 1024 * 1024, // 1MB
	})

	for _, valueStr := range []string{
		"I am the very model of a modern Major-General",
		"I've information vegetable, animal, and mineral",
		"I know the kings of England, and I quote the fights historical",
		"From Marathon to Waterloo, in order categorical",
		"I'm very well acquainted, too, with matters mathematical",
		"I understand equations, both the simple and quadratical",
		"About binomial theorem I'm teeming with a lot o' news",
		"With many cheerful facts about the square of the hypotenuse",
	} {
		d.Write(md5sum(valueStr), []byte(valueStr))
	}

	var keyCount int
	for key := range d.Keys(nil) {
		val, err := d.Read(key)
		if err != nil {
			panic(fmt.Sprintf("key %s had no value", key))
		}
		fmt.Printf("%s: %s\n", key, val)
		keyCount++
	}
	fmt.Printf("%d total keys\n", keyCount)

	// d.EraseAll() // leave it commented out to see how data is kept on disk
}