How to download the video with a resolution less than or equal to 720p and with audio.

[EugenSmith]

Hello, all!
I use embedded youtube-dl in python script for download video with a resolution less than or equal to 720p. Video successfully downloaded but without audio.
Could somebody offer some advice. How to download the video with a resolution less than or equal to 720p and with audio?

#!/usr/bin/env python

# encoding: utf-8
from __future__ import unicode_literals
import os, sys, youtube_dl

def download(url):
     ydl_options = {
         "outtmpl":           "%(id)s.%(ext)s",
         "writethumbnail": True,        
         "addmetadata": True,
         "format": "bestvideo/best[height<=720]+bestaudio/best[height<=720]",
         "continuedl": True,
         "quiet": False,
         "restrictfilenames": False,
         "ignoreerrors": True
     }
     with youtube_dl.YoutubeDL(ydl_options) as ydl:
        try:
            ydl.download([url])
        except (youtube_dl.utils.DownloadError,youtube_dl.utils.ContentTooShortError,youtube_dl.utils.ExtractorError) as e:
            print(e)      

def main():
    download(str(sys.argv[1]))    

if __name__ == "__main__":
    main()

[dstftw]

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