public static function color($text, $foreground, $background = null)
    {
        $foreground = self::$colors[$foreground];
        $code = "\x03".$foreground;
        
        if ($background !== null) {
            $background = self::$colors[$background];
            $code .= ','.$background;
        }
        
        return $code.$text."\x03";
    }