'Produce an OVER clause against this function.
Used against aggregate or so-called "window" functions,
for database backends that support window functions.
The expression::
func.row_number().over(order_by=\'x\')
is shorthand for::
from sqlalchemy import over
over(func.row_number(), order_by=\'x\')
See :func:`~.expression.over` for a full description.
.. versionadded:: 0.7'

def over(self, partition_by=None, order_by=None):

    return Over(self, partition_by=partition_by, order_by=order_by)
