public static function string($string, $foreground_colour = null, $background_colour = null)
    {
        $coloured_string = "";

        // Check if given foreground colour found
        if (isset(self::$foreground_colours[$foreground_colour])) {
            $coloured_string .= self::getForegroundCode($foreground_colour);
        }
        // Check if given background colour found
        if (isset(self::$background_colours[$background_colour])) {
            $coloured_string .= self::getBackgroundCode($background_colour);
        }

        // Add string and end colouring
        $coloured_string .= $string . self::getResetCode();

        return $coloured_string;
    }