title: How to send message with @ID telegram using telethon library
body: <p>I want send message with telethon but i dont have phone number this .
  i have only @username Telegram.
  with this code i can send message for my contact phone :</p>
  
  <pre><code>result = client.invoke(ImportContactsRequest([contact], replace=True))
  contacts = client.invoke(GetContactsRequest(""))
  for u in result.users:
      client.send_message(u, 'Hi')
  </code></pre>
  
  <p>But i want send message to @username Telegram</p>