sub io_led {
    my ($self, $tweak) = @_;
 
    if ($tweak){
        # stop disk activity from operating the green LED
        `echo none | sudo tee /sys/class/leds/led0/trigger`;
        # turn on the green LED full-time
        `echo 1 | sudo tee /sys/class/leds/led0/brightness`;
    }
    else {
        # turn off the green LED from being on full-time
        `echo 0 | sudo tee /sys/class/leds/led0/brightness`;
        # start disk activity operating the green LED
        `echo mmc0 | sudo tee /sys/class/leds/led0/trigger`;
    }
}
sub pwr_led {
    my ($self, $tweak) = @_;
 
    if ($tweak){
        # turn off the red power LED
        `echo 0 | sudo tee /sys/class/leds/led1/brightness`;
    }
    else {
        # restore default power LED operation
        `echo input | sudo tee /sys/class/leds/led1/trigger`;
    }
}