#!/usr/bin/env python
import smbus
import time
bus = smbus.SMBus(1)
address = 0x39
register = 0x15

b = bus.read_byte_data(address,register)
print(b)
bus.close()

where address is result of i2cdetect -y 0 or -y 1,
where register is location of requested data from Addr (hex)