title: Model by name in SQLAlchemy
body: <p>Is it possible to get an ORM-mapped model class from name? </p>
  
  <p>Definitely SQLAlchemy has this functionality built-in somewhere. For instance in declarative style you can write things like <code>blahs = relationship('Blah')</code> (notice: no module prefix required). I tried looking inside <code>sqlalchemy.orm.properties.RelationshipProperty</code> but can't figure out when <code>argument</code> string is replaced by the actual thing.</p>