title: Problem in initialising connection with Telethon
body: <p>I'm trying to get to the Telegram API through Telethon Library. But I can't even start the connection. 
  The code here is the sample code suggested in <a href="https://docs.telethon.dev/en/latest/basic/signing-in.html" rel="nofollow noreferrer">the official guide</a>. </p>
  
  <pre><code># Use your own values from my.telegram.org
  api_id = ***
  api_hash = '***'
  
  # The first parameter is the .session file name (absolute paths allowed)
  async with TelegramClient('new_session', api_id, api_hash) as client:
      client.loop.run_until_complete(client.send_message('me', 'Hello, myself!'))
      client.run_until_disconnected()
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Please enter your phone (or bot token): 
  ---------------------------------------------------------------------------
  AuthKeyUnregisteredError                  Traceback (most recent call last)
  /usr/local/lib/python3.7/site-packages/telethon/client/users.py in is_user_authorized(self)
      190                 # Any request that requires authorization will work
  --&gt; 191                 await self(functions.updates.GetStateRequest())
      192                 self._authorized = True
  </code></pre>
  
  <p>...</p>
  
  <pre><code>AuthKeyUnregisteredError: The key is not registered in the system (caused by GetStateRequest)
  
  During handling of the above exception, another exception occurred:
  
  EOFError                                  Traceback (most recent call last)
  &lt;ipython-input-23-71009056fead&gt; in async-def-wrapper()
        7     client.loop.run_until_complete(client.send_message('me', 'Hello, myself!'))
        8     client.run_until_disconnected()
  ----&gt; 9 
  
  /usr/local/lib/python3.7/site-packages/telethon/client/auth.py in __aenter__(self)
      634 
      635     async def __aenter__(self):
  --&gt; 636         return await self.start()
      637 
      638     async def __aexit__(self, *args):
  
  /usr/local/lib/python3.7/site-packages/telethon/client/auth.py in _start(self, phone, password, bot_token, force_sms, code_callback, first_name, last_name, max_attempts)
      145             # Turn the callable into a valid phone number (or bot token)
      146             while callable(phone):
  --&gt; 147                 value = phone()
      148                 if inspect.isawaitable(value):
      149                     value = await value
  
  /usr/local/lib/python3.7/site-packages/telethon/client/auth.py in &lt;lambda&gt;()
       18     def start(
       19             self: 'TelegramClient',
  ---&gt; 20             phone: typing.Callable[[], str] = lambda: input('Please enter your phone (or bot token): '),
       21             password: typing.Callable[[], str] = lambda: getpass.getpass('Please enter your password: '),
       22             *,
  
  EOFError: EOF when reading a line
  </code></pre>
  
  <p>The error suggests that: </p>
  
  <pre><code>The key is not registered in the system (caused by GetStateRequest)
  </code></pre>
  
  <p>But I got the app_id and api_hash from my.telegram.org.</p>