Ошибка TypeError: one character string expected в примере библиотеки Adafruit_ADS1x15 Python

не получается запустить код с примера библиотеки Adafruit_ADS1x15 Python. Система Raspberry Pi3. Открывал доступ I2C. Ошибка:

pi@raspberrypi:~/Desktop/11/Adafruit_Python_ADS1x15/examples $ sudo python simpletest.py
Reading ADS1x15 values, press Ctrl-C to quit...
|      0 |      1 |      2 |      3 |
-------------------------------------
Traceback (most recent call last):
  File "simpletest.py", line 42, in <module>
    values[i] = adc.read_adc(i, gain=GAIN)
  File "build/bdist.linux-armv7l/egg/Adafruit_ADS1x15/ADS1x15.py", line 192, in read_adc
  File "build/bdist.linux-armv7l/egg/Adafruit_ADS1x15/ADS1x15.py", line 133, in _read
  File "build/bdist.linux-armv7l/egg/Adafruit_GPIO/I2C.py", line 136, in readList
  File "build/bdist.linux-armv7l/egg/Adafruit_PureIO/smbus.py", line 216, in read_i2c_block_data
TypeError: one character string expected
pi@raspberrypi:~/Desktop/11/Adafruit_Python_ADS1x15/examples $