docs: def _set_i2c_speed(self, i2c_speed):
          """ Set I2C speed to one of '400kHz', '100kHz', 50kHz', '5kHz'
          """
          lower_bits_mapping = {
              '400kHz': 3,
              '100kHz': 2,
              '50kHz': 1,
              '5kHz': 0,
          }
          if i2c_speed not in lower_bits_mapping:
              raise ValueError('Invalid i2c_speed')
          speed_byte = 0b01100000 | lower_bits_mapping[i2c_speed]
          self.device.write(bytearray([speed_byte]))
          response = self.device.read(1)
          if response != b"\x01":
              raise Exception("Changing I2C speed failed. Received: {}".format(repr(response)))