code: public function log( $message, $severity = self::INFO )
      {
          if ( !isset( $this->names[$severity] ) )
          {
              throw new \RuntimeException( "Unknown severity: " . $severity );
          }
  
          printf( "        <li>
              <span style=\"color: #babdb6\">%s</span> %s
              <span style=\"color: %s; font-weight: bold;\">%s:</span> %s
          </li>\n",
              date( DATE_RFC1036 ),
              ( $this->task ?
                  $this->task . (
                      $this->command ?
                          '::' . $this->command :
                          ''
                  . ' ' ) :
                  ''
              ),
              $this->colors[$severity],
              $this->names[$severity],
              $message
          );
          flush();
      }
docs: Log message
  
  Log a message, while the message must be convertable into a string.
  Optionally a log message severity can be specified.
  
  @param string $message
  @param int $severity
  @return void