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: docs.go
    path of file: ./repos/teller/vendor/github.com/urfave/cli/v2
    
    the code of the file until where you have to start completion: //go:build !urfave_cli_no_docs
// +build !urfave_cli_no_docs

package cli

import (
	"bytes"
	"fmt"
	"io"
	"sort"
	"strings"
	"text/template"

	"github.com/cpuguy83/go-
    
func (a *App) ToManWithSection(sectionNumber int) (string, error) {
	var w bytes.Buffer
	if err := a.writeDocTemplate(&w, sectionNumber); err != nil {
		return "", err
	}
	man := md2man.Render(w.Bytes())
	return string(man), nil
}