title: Python clickhouse_driver through ssh connection error
body: <p>struggling for a week already with my issue, hope you'll be able to explain to me what is wrong here.</p>
  <p>I'm trying to connect Clickhouse DB I have on the remote server, which is on the absolutely default settings. So I'm connecting to a remote server and creating a tunnel on my machine.</p>
  <pre><code>import sshtunnel as sshtunnel
  from clickhouse_driver import connect
  
  server = sshtunnel.SSHTunnelForwarder(
      ('host', 22),
      ssh_username='username',
      ssh_pkey=&quot;username.openssh&quot;,
      ssh_private_key_password=&quot;password&quot;,
      remote_bind_address=('localhost', 8123),
      local_bind_address=('localhost', 555)
  )
  
  server.start()
  conn = connect(host='localhost', port=555, database='ertb')
  cursor = conn.cursor()
  cursor.execute('SHOW TABLES')
  cursor.fetchall()
  server.stop()
  </code></pre>
  <p>and I receive this error</p>
  <pre><code>Traceback (most recent call last):
    File &quot;C:/Users/user/PycharmProjects/alerts/ssh_coonection.py&quot;, line 42, in &lt;module&gt;
      cursor.execute('SHOW TABLES')
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\dbapi\cursor.py&quot;, line 102, in execute
      **execute_kwargs
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\client.py&quot;, line 205, in execute
      self.connection.force_connect()
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\connection.py&quot;, line 180, in force_connect
      self.connect()
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\connection.py&quot;, line 256, in connect
      return self._init_connection(host, port)
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\connection.py&quot;, line 237, in _init_connection
      self.send_hello()
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\connection.py&quot;, line 325, in send_hello
      write_binary_str(self.user, self.fout)
    File &quot;C:\Users\user\PycharmProjects\alerts\venv\lib\site-packages\clickhouse_driver\writer.py&quot;, line 19, in write_binary_str
      text = text.encode('utf-8')
  AttributeError: 'NoneType' object has no attribute 'encode'
  </code></pre>
  <p>I really tried to understand from where this NoneType object appears, but a bit stuck in code.</p>