title: youtube-dl python library documentation
body: <p>is there any documentation for use youtube-dl as a python library in a project?</p>
  
  <p>I know that I can use the main class, but I can't find any documentation or example...</p>
  
  <pre><code>import youtube_dl
  
  ydl = youtube_dl.YoutubeDL(params)
  
  ... ?
  </code></pre>