BeagleBone Blink Custom LED on P9 - PIN 15

import os
import time

os.system("echo 48 > /sys/class/gpio/export")
os.system("echo out > /sys/class/gpio/gpio48/direction")

on = 0
while(True):
    tmp_string = ""
    if on == 0:
        tmp_string = "echo 1 > /sys/class/gpio/gpio48/value"
        on = 1
    elif on == 1:
        tmp_string = "echo 0 > /sys/class/gpio/gpio48/value"
        on = 0

    if tmp_string != "":
        os.system(tmp_string)
    time.sleep(0.5)