In other words, the ``Default`` group and the class name group (e.g. ``User``) are identical,

except when the class is embedded in another object that's actually the one being validated.

In case you have inheritance in your data model and you validate with the class name of

the subclass in the subclass and in the baseclass all constraints in the default group

will be validated. If you use the name of the baseclass only the constraints in the base

class will be validated.

If you have inheritance (e.g. ``User extends BaseUser``) and you validate

with the class name of the subclass (i.e. ``User``), then all constraints

in the ``User`` and ``BaseUser`` will be validated. However, if you validate

using the base class (i.e. ``BaseUser``), then only the constraints in

the ``BaseUser`` group will be validated.

To tell the validator to use a specific group, pass one or more group names

as the second argument to the ``validate()`` method::