title: SQLalchemy query get aggregate array of dicts
body: <p>Is it possible to get an aggregate array containing dictionaries from an SQLAlchemy query? e.g.</p>
  
  <pre><code>session.query(
      Object.name,
      func.array_agg({Location.id: Location.name}).label('locations')
  )\
      .join(Location)\
      .all()
  </code></pre>
  
  <p>So the expected result will be:</p>
  
  <pre><code>[
   ('Horizontal neutral circuit',
    [{143:'A5'},{145:'A8'},{765:'B12'}]),
   ('Fletcher, Lopez and Edwards',
    [{41:'A1'},{76:'B8'},{765:'B12'}]),
  ]
  </code></pre>