code: def _read_register(self, reg):
          
          self.buf[0] = reg
          with self.i2c_device as i2c:
              i2c.write(self.buf, end=1, stop=False)
              i2c.readinto(self.buf, end=2)
          return self.buf[0] << 8 | self.buf[1]
docs: Read 16 bit register value.