'Generate a data dict (self._data) from the Homematic metadata.'

def _init_data_struct(self):

    self._state = next(iter(self._hmdevice.WRITENODE.keys()))
    self._data[self._state] = STATE_UNKNOWN
    if (HM_CONTROL_MODE in self._hmdevice.ATTRIBUTENODE):
        self._data[HM_CONTROL_MODE] = STATE_UNKNOWN
    for node in self._hmdevice.SENSORNODE.keys():
        self._data[node] = STATE_UNKNOWN
