title: Python Pytube progress for playlist download
body: <p>I am writing a program in python using pytube, and I want to indicate progress when downloading a playlist. When downloading a single video I can do:</p>
  
  <pre><code>YouTube(url, on_progress_callback=progressFunction)
  </code></pre>
  
  <p>but that doesn't work when downloading a playlist:</p>
  
  <pre><code>Playlist(url, on_progress_callback=progressFunction)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>TypeError: __init__() got an unexpected keyword argument 'on_progress_callback'
  </code></pre>
  
  <p>Is there any way to get the progress when downloading a playlist?</p>