'Return the class-bound descriptor corresponding to this
:class:`.MapperProperty`.
This is basically a ``getattr()`` call::
return getattr(self.parent.class_, self.key)
I.e. if this :class:`.MapperProperty` were named ``addresses``,
and the class to which it is mapped is ``User``, this sequence
is possible::
>>> from sqlalchemy import inspect
>>> mapper = inspect(User)
>>> addresses_property = mapper.attrs.addresses
>>> addresses_property.class_attribute is User.addresses
True
>>> User.addresses.property is addresses_property
True'

@property
def class_attribute(self):

    return getattr(self.parent.class_, self.key)
