code: public static function log($strText, $strFunction, $strCategory)
  	{
  		@trigger_error('Using System::log() has been deprecated and will no longer work in Contao 5.0. Use the logger service instead.', E_USER_DEPRECATED);
  
  		$level = 'ERROR' === $strCategory ? LogLevel::ERROR : LogLevel::INFO;
  		$logger = static::getContainer()->get('monolog.logger.contao');
  
  		$logger->log($level, $strText, array('contao' => new ContaoContext($strFunction, $strCategory)));
  	}
docs: Add a log entry to the database
  
  @param string $strText     The log message
  @param string $strFunction The function name
  @param string $strCategory The category name
  
  @deprecated Deprecated since Contao 4.2, to be removed in Contao 5.
  Use the logger service instead.