'Call the ``init()`` method on all ``MapperProperties``
attached to this mapper.
This is a deferred configuration step which is intended
to execute once all mappers have been constructed.'

def _post_configure_properties(self):

    self._log('_post_configure_properties()    started')
    l = [(key, prop) for (key, prop) in self._props.items()]
    for (key, prop) in l:
        self._log('initialize    prop    %s', key)
        if ((prop.parent is self) and (not prop._configure_started)):
            prop.init()
        if prop._configure_finished:
            prop.post_instrument_class(self)
    self._log('_post_configure_properties()    complete')
    self.configured = True
