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: attrs.go
    path of file: ./repos/whatsmeow/binary
    
    the code of the file until where you have to start completion: // Copyright (c) 2021 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// fil
    
func (au *AttrUtility) GetUnixMilli(key string, require bool) (time.Time, bool) {
	if intVal, ok := au.GetInt64(key, require); !ok {
		return time.Time{}, false
	} else if intVal == 0 {
		return time.Time{}, true
	} else {
		return time.UnixMilli(intVal), true
	}
}