title: How to use READ ONLY transaction mode in SQLAlchemy?
body: <p>In PostgreSQL transaction access mode can be changed to <code>READ ONLY</code> (<a href="http://www.postgresql.org/docs/devel/static/sql-set-transaction.html" rel="noreferrer">docs</a>). In SQLAlchemy, isolation level can be changed for an engine, but no parameter is provided for read-only access mode (<a href="http://docs.sqlalchemy.org/en/latest/core/connections.html#sqlalchemy.engine.Connection.execution_options.params.isolation_level" rel="noreferrer">docs</a>).</p>
  
  <p>How to make an engine with <code>READ ONLY</code> access mode on connections?</p>