title: Get group media count in telethon
body: <p>How can i get the number of sent media (photos,videos,voices,...) in a chat,group or channel using python telegram api library(<a href="https://github.com/LonamiWebs/Telethon" rel="nofollow noreferrer">telethon</a>)?</p>
  
  <p>I checked <code>GetFullChannelRequest</code> but it didn't get the number of media.</p>