title: Access remote DB via ssh tunnel (Python 3)
body: <p>I can not understand (even after reading few articles dedicated to ssh tunelling) what parameters of CLI ssh command where in this script.
  Basically I have to connect to some server (I called it 'ssh_tunnel_host:22'), than connect to db_host using this tunnel.</p>
  
  <pre><code>with SSHTunnelForwarder(
      ('ssh_tunnel_host', 22),
      ssh_username="ssh_username",
      ssh_pkey="/somepath/id_rsa",
      local_bind_address=('0.0.0.0', 1234),
      remote_bind_address=('127.0.0.1', 3306)
  ) as tunnel:
      client = paramiko.SSHClient()
      client.load_system_host_keys()
      client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
      client.connect('127.0.0.1', 1234)
      db_connection = pymysql.connect(host=db_host, port=3306, db='mysql', user='user',
                                      password='password', charset='utf8mb4')
  </code></pre>
  
  <p>Could someone explain to me:</p>
  
  <ol>
  <li>What is local_bind_address - is it my local address or ssh_tunnel_host local adderss? Where can I learn IP and port?</li>
  <li>Depends on previous question - what is remote_bind_address - is it address of ssh_tunnel_host or db_host? Where can I learn these IP and port?</li>
  <li>Where should I connect with client.connect()? Local or remote bind?</li>
  </ol>
  
  <p>(I did try to read the docs but it is still messing)</p>