'Return the state of the sensor.'

@property
def state(self):

    if (self._matrix is None):
        return None
    _data = self._matrix['rows'][0]['elements'][0]
    if ('duration_in_traffic' in _data):
        return round((_data['duration_in_traffic']['value'] / 60))
    if ('duration' in _data):
        return round((_data['duration']['value'] / 60))
    return None
