def _is_efficient_filtering_enabled(self) -> bool:
        """Check if kNN with efficient filtering is enabled."""
        # Technically, AOSS supports efficient filtering,
        # but we can't check the version number using .info(); AOSS doesn't support 'GET /'
        #  so we must skip and disable by default.
        if self.is_aoss:
            ef_enabled = False
        else:
            self._os_version = self._get_opensearch_version()
            major, minor, patch = self._os_version.split(".")
            ef_enabled = int(major) >= 2 and int(minor) >= 9
        return ef_enabled
Check if kNN with efficient filtering is enabled.
llama-index-integrations/vector_stores/llama-index-vector-stores-opensearch/llama_index/vector_stores/opensearch/base.py