code: private static function checkLevel($level)
      {
          if ($level != LogLevel::ALERT && $level != LogLevel::CRITICAL && $level != LogLevel::DEBUG && //
          $level != LogLevel::EMERGENCY && $level != LogLevel::ERROR && $level != LogLevel::INFO && //
          $level != LogLevel::NOTICE && $level != LogLevel::WARNING) {
              throw new \Psr\Log\InvalidArgumentException("Invalid log level provided!");
          }
      }
docs: Checks the given level
  
  @param string $level
  @throws \Psr\Log\InvalidArgumentException