title: telethon: filtering events by the type of the chats they are coming from
body: <p>i wanna filter the <code>events.newMessage</code> to fire only when messages are coming from private chats.
  but i don't want to put all chat ids in chats list argument of the event</p>
  
  <p>do you have any ideas ?</p>
  
  <pre><code>@client.on(events.NewMessage)
  async def my_event_handler(event):
      if 'hello' in event.raw_text:
          await client.delete_messages(await event.get_chat(), event.id)
  </code></pre>
  
  <p>in the example above think i a want to delete all messages coming from private chats ( everyone of them )</p>