'Return a new :class:`.Query` object transformed by
the given function.
E.g.::
def filter_something(criterion):
def transform(q):
return q.filter(criterion)
return transform
q = q.with_transformation(filter_something(x==5))
This allows ad-hoc recipes to be created for :class:`.Query`
objects.  See the example at :ref:`hybrid_transformers`.
.. versionadded:: 0.7.4'

def with_transformation(self, fn):

    return fn(self)
