use Psr\Log\LoggerInterface; use Psr\Log\LogLevel; // Instantiate a Logger $logger = new MyLogger(); // Log a warning $logger->log(LogLevel::WARNING, 'This is a warning message.');In the example above, we defined a logger class called "MyLogger", which implements the PSR-3 LoggerInterface. Then, we instantiated an instance of this logger and logged a warning message using the LogLevel::WARNING constant. The PHP Logger warning is typically used in conjunction with other log levels, such as error, info, and debug, to provide a comprehensive overview of an application's behavior. It is also often used with a package library such as Monolog or Log4PHP.