input_readers.py 文件源码

def _iter_key_range(self, k_range):
    """Yields a db.Key and the value that should be yielded by self.__iter__().

    Args:
      k_range: The key_range.KeyRange to iterate over.

    Yields:
      A 2-tuple containing the last db.Key processed and the value that should
      be yielded by __iter__. The returned db.Key will be used to determine the
      InputReader's current position in self._current_key_range.
    """
    raise NotImplementedError("_iter_key_range() not implemented in %s" %
                              self.__class__)