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: cover.go
    path of file: ./repos/tview/demos/presentation
    
    the code of the file until where you have to start completion: package main

import (
	"fmt"
	"strings"

	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

const logo = `
   __        _
  / /__   __(_)__ _      __
 / __/ | / / / _ \ | /| / /
/ /_ | |/ / /  __/ |/ |/ /
\__/ |___/_/\___/|__/|__/

`

const (
	subtitle   = `tview - Rich Widgets for Terminal UIs`
	navigation = `[yellow]Ctrl-N[-]: Next slide    [yellow]Ctrl-P[-]: Previous slide    [yellow]Ctrl-C[-]: Exit`
	mouse      = `(or use your mouse)`
)

// Cover returns the cover page.
func Cover(nextSlide func()) (title string, content tview.Primitive) {
	// What's the size of the logo?
	lines := strings.Split(logo, "\n")
	logoWidth := 0
	logoHeight := len(lines)
	for _, line := range lines {
		if len(line) > logoWidth {
			logoWidth = len(li
    
func Cover(nextSlide func()) (title string, content tview.Primitive) {
	// What's the size of the logo?
	lines := strings.Split(logo, "\n")
	logoWidth := 0
	logoHeight := len(lines)
	for _, line := range lines {
		if len(line) > logoWidth {
			logoWidth = len(line)
		}
	}
	logoBox := tview.NewTextView().
		SetTextColor(tcell.ColorGreen).
		SetDoneFunc(func(key tcell.Key) {
			nextSlide()
		})
	fmt.Fprint(logoBox, logo)

	// Create a frame for the subtitle and navigation infos.
	frame := tview.NewFrame(tview.NewBox()).
		SetBorders(0, 0, 0, 0, 0, 0).
		AddText(subtitle, true, tview.AlignCenter, tcell.ColorWhite).
		AddText("", true, tview.AlignCenter, tcell.ColorWhite).
		AddText(navigation, true, tview.AlignCenter, tcell.ColorDarkMagenta).
		AddText(mouse, true, tview.AlignCenter, tcell.ColorDarkMagenta)

	// Create a Flex layout that centers the logo and subtitle.
	flex := tview.NewFlex().
		SetDirection(tview.FlexRow).
		AddItem(tview.NewBox(), 0, 7, false).
		AddItem(tview.NewFlex().
			AddItem(tview.NewBox(), 0, 1, false).
			AddItem(logoBox, logoWidth, 1, true).
			AddItem(tview.NewBox(), 0, 1, false), logoHeight, 1, true).
		AddItem(frame, 0, 10, false)

	return "Start", flex
}