'Produce the "row processing" function for this :class:`.Bundle`.
May be overridden by subclasses.
.. seealso::
:ref:`bundles` - includes an example of subclassing.'

def create_row_processor(self, query, procs, labels):

    def proc(row, result):
        return util.KeyedTuple([proc(row, None) for proc in procs], labels)
    return proc
