public function save_meta_data() {
		if ( ! $this->data_store || is_null( $this->meta_data ) ) {
			return;
		}
		foreach ( $this->meta_data as $array_key => $meta ) {
			if ( is_null( $meta->value ) ) {
				if ( ! empty( $meta->id ) ) {
					$this->data_store->delete_meta( $this, $meta );
					unset( $this->meta_data[ $array_key ] );
				}
			} elseif ( empty( $meta->id ) ) {
				$meta->id = $this->data_store->add_meta( $this, $meta );
				$meta->apply_changes();
			} else {
				if ( $meta->get_changes() ) {
					$this->data_store->update_meta( $this, $meta );
					$meta->apply_changes();
				}
			}
		}
		if ( ! empty( $this->cache_group ) ) {
			$cache_key = WC_Cache_Helper::get_cache_prefix( $this->cache_group ) . WC_Cache_Helper::get_cache_prefix( 'object_' . $this->get_id() ) . 'object_meta_' . $this->get_id();
			wp_cache_delete( $cache_key, $this->cache_group );
		}
	}