'Construct a query for this key range, including the scan direction.
Args:
kind: A string.
keys_only: bool, default False, use keys_only on Query?
Returns:
A datastore.Query instance.
Raises:
KeyRangeError: if self.direction is not in (KeyRange.ASC, KeyRange.DESC).'

def make_directed_datastore_query(self, kind, keys_only=False):

    direction = self.__get_direction(datastore.Query.ASCENDING, datastore.Query.DESCENDING)
    query = datastore.Query(kind, _app=self._app, keys_only=keys_only)
    query.Order(('__key__', direction))
    query = self.filter_datastore_query(query)
    return query
