-The EntityProxyFields defined in this file can be assigned as fields on
-a subclass of philo.models.Entity. They act like any other model
-fields, but instead of saving their data to the database, they save it
-to attributes related to a model instance. Additionally, a new
-attribute will be created for an instance if and only if the field's
-value has been set. This is relevant i.e. for passthroughs, where the
-value of the field may be defined by some other instance's attributes.
+EntityProxyFields can be assigned as fields on a subclass of philo.models.Entity. They act like any other model fields, but instead of saving their data to the model's table, they save it to attributes related to a model instance. Additionally, a new attribute will be created for an instance if and only if the field's value has been set. This is relevant i.e. for :class:`QuerySetMapper` passthroughs, where even an Attribute with a value of ``None`` must prevent a passthrough.