title: With statement and SQLalchemy engine
body: <p>When I try to implement SQLalchemy engine using following construction</p>
  
  <pre><code>with sqlalchemy.create_engine("sqlite:///my_db.sqlite") as engine:
       (do something)
  </code></pre>
  
  <p>I get an error: <code>AttributeError: __exit__</code></p>
  
  <p>What is wrong? And how can I explicitly close my SQLalchemy engine?</p>