def device_key(self, device_key):
        """
        Sets the device_key of this DeviceData.
        The fingerprint of the device certificate.

        :param device_key: The device_key of this DeviceData.
        :type: str
        """
        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