code: def device_key(self, device_key):
          
          if device_key is not None and len(device_key) > 512:
              raise ValueError("Invalid value for `device_key`, length must be less than or equal to `512`")
  
          self._device_key = device_key
docs: Sets the device_key of this DeviceData.
          The fingerprint of the device certificate.
  
          :param device_key: The device_key of this DeviceData.
          :type: str