public function maybe_filter( WP_Query $wp_query ) {

		if ( empty( $wp_query->query['post_type'] ) || ! in_array( $this->post_type, (array) $wp_query->query['post_type'], true ) ) {
			return;
		}

		$vars = self::get_filter_vars( $wp_query->query, $this->args['site_filters'] );

		if ( empty( $vars ) ) {
			return;
		}

		foreach ( $vars as $key => $value ) {
			if ( is_array( $value ) ) {
				$query = $wp_query->get( $key );
				if ( empty( $query ) ) {
					$query = [];
				}
				$value = array_merge( $query, $value );
			}
			$wp_query->set( $key, $value );
		}

	}