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: qr.go
    path of file: ./repos/corteza/server/vendor/rsc.io/qr
    
    the code of the file until where you have to start completion: // Copyright 2011 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

/*
Package qr encodes QR codes.
*/
package qr // import "rsc.io/qr"

import (
	"errors"
	"image"
	"image/color"

	"rsc.io/qr/coding"
)

// A Level denotes a QR error correction level.
// From least to most tolerant of errors, they are L, M, Q, H.
type Level int

const (
	L Level = iota // 20% redundant
	M              // 38% redundant
	Q              // 55% redundant
	H              // 65% redundant
)

// Encode returns an encoding of text at the given error correction level.
func 
    
func Encode(text string, level Level) (*Code, error) {
	// Pick data encoding, smallest first.
	// We could split the string and use different encodings
	// but that seems like overkill for now.
	var enc coding.Encoding
	switch {
	case coding.Num(text).Check() == nil:
		enc = coding.Num(text)
	case coding.Alpha(text).Check() == nil:
		enc = coding.Alpha(text)
	default:
		enc = coding.String(text)
	}

	// Pick size.
	l := coding.Level(level)
	var v coding.Version
	for v = coding.MinVersion; ; v++ {
		if v > coding.MaxVersion {
			return nil, errors.New("text too long to encode as QR")
		}
		if enc.Bits(v) <= v.DataBytes(l)*8 {
			break
		}
	}

	// Build and execute plan.
	p, err := coding.NewPlan(v, l, 0)
	if err != nil {
		return nil, err
	}
	cc, err := p.Encode(enc)
	if err != nil {
		return nil, err
	}

	// TODO: Pick appropriate mask.

	return &Code{cc.Bitmap, cc.Size, cc.Stride, 8}, nil
}