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: version.go
    path of file: ./repos/govendor/context
    
    the code of the file until where you have to start completion: // Copyright 2016 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 context

import (
	"strconv"
	"unicode"
)

// IsVersion returns true if the string is a version.
func isVersion(s string) bool {
	hasPunct := false
	onlyNumber := true
	onlyHexLetter := true
	for _, r := range s {
		isNumber := unicode.IsNumber(r)
		isLetter := unicode.I
    
func isVersion(s string) bool {
	hasPunct := false
	onlyNumber := true
	onlyHexLetter := true
	for _, r := range s {
		isNumber := unicode.IsNumber(r)
		isLetter := unicode.IsLetter(r)

		hasPunct = hasPunct || unicode.IsPunct(r)
		onlyNumber = onlyNumber && isNumber

		if isLetter {
			low := unicode.ToLower(r)
			onlyHexLetter = onlyHexLetter && low <= 'f'
		}
	}
	if hasPunct {
		return true
	}
	if !onlyHexLetter {
		return true
	}

	num, err := strconv.ParseInt(s, 10, 64)
	if err == nil {
		if num > 100 {
			return false // numeric revision.
		}
	}

	if len(s) > 5 && onlyHexLetter {
		return false // hex revision
	}
	return true
}