wp-notices.php
private function restore_global( $id ) {
		$id     = self::$instance->get_id( $id );
		$notice = self::$instance->get_notice( $id );

		if ( false === $notice ) {
			return false;
		}

		$dismissed = self::$instance->dismissed_global();

		if ( ! in_array( $id, $dismissed ) ) {
			return false;
		}

		$flip = array_flip( $dismissed );
		$key  = $flip[ $id ];

		unset( $dismissed[ $key ] );
		return update_option( 'tdp_dismissed_notices', $dismissed );
	}
private function restore_global( $id ) {
		$id     = self::$instance->get_id( $id );
		$notice = self::$instance->get_notice( $id );

		if ( false === $notice ) {
			return false;
		}

		$dismissed = self::$instance->dismissed_global();

		if ( ! in_array( $id, $dismissed ) ) {
			return false;
		}

		$flip = array_flip( $dismissed );
		$key  = $flip[ $id ];

		unset( $dismissed[ $key ] );
		return update_option( 'tdp_dismissed_notices', $dismissed );
	}
Restore a globally dismissed notice.

@param string $id
@return void