title: sqlalchemy.exc.ResourceClosedError: This Connection is closed when inserting after select
body: <p>I am doing a <code>select()</code> from a SQLite database and then an <code>insert()</code>:</p>
  
  <pre><code>engine = create_engine('sqlite:///testdb.db')
  metadata = MetaData(bind=engine)
  test = Table('test', metadata, autoload=True)
  
  # Select all from pending_data
  sel = select([test])
  res = engine.execute(sel)
  
  print res
  
  # do an insert into pending_data
  test.insert()\
      .values(info='blah')\
      .execute()
  </code></pre>
  
  <p>When my code executes the insert line, I get this error:</p>
  
  <pre><code>sqlalchemy.exc.ResourceClosedError: This Connection is closed
  </code></pre>
  
  <p>However, if I convert my res into a list like so:</p>
  
  <pre><code>res = list(engine.execute(sel))
  </code></pre>
  
  <p>My code runs fine.  What's going on here?</p>