def get_prefix(self, key_prefix, sort_order=None, sort_target=None):
        """Get a range of keys with a prefix.

        :param sort_order: 'ascend' or 'descend' or None
        :param key_prefix: first key in range

        :returns: sequence of (value, metadata) tuples
        """
        return self.get(key_prefix,
                        metadata=True,
                        range_end=_encode(_increment_last_byte(key_prefix)),
                        sort_order=sort_order,
                        sort_target=sort_target)