code: def start_adc(self, channel, gain=1, data_rate=None):
          
          assert 0 <= channel <= 3, 'Channel must be a value within 0-3!'
          # Start continuous reads and set the mux value to the channel plus
          # the highest bit (bit 3) set.
          return self._read(channel + 0x04, gain, data_rate, ADS1x15_CONFIG_MODE_CONTINUOUS)
docs: Start continuous ADC conversions on the specified channel (0-3). Will
          return an initial conversion result, then call the get_last_result()
          function to read the most recent conversion result. Call stop_adc() to
          stop conversions.