I've solved it. Here is my code in python:
def set_led(indicator_name, indicator_number, brightness):
dev_name = '/sys/class/leds/status:white:%(indicator_name)s%(indicator_number)d/brightness' % \
{'indicator_name': indicator_name, 'indicator_number': indicator_number}
f = open(dev_name, mode='w')
f.write("%(brightness)d" % {'brightness': brightness})
f.close()