def keys(self):
        """
        Access the keys

        :returns: twilio.rest.preview.deployed_devices.fleet.key.KeyList
        :rtype: twilio.rest.preview.deployed_devices.fleet.key.KeyList
        """
        if self._keys is None:
            self._keys = KeyList(self._version, fleet_sid=self._solution['sid'], )
        return self._keys