'Initialize the sensor.'

def __init__(self, hass, name, indoor_temp_sensor, outdoor_temp_sensor, indoor_humidity_sensor, calib_factor):

    self._state = None
    self._name = name
    self._indoor_temp_sensor = indoor_temp_sensor
    self._indoor_humidity_sensor = indoor_humidity_sensor
    self._outdoor_temp_sensor = outdoor_temp_sensor
    self._calib_factor = calib_factor
    self._is_metric = hass.config.units.is_metric
    self._dewpoint = None
    self._indoor_temp = None
    self._outdoor_temp = None
    self._indoor_hum = None
    self._crit_temp = None
    track_state_change(hass, indoor_temp_sensor, self._sensor_changed)
    track_state_change(hass, outdoor_temp_sensor, self._sensor_changed)
    track_state_change(hass, indoor_humidity_sensor, self._sensor_changed)
    indoor_temp = hass.states.get(indoor_temp_sensor)
    outdoor_temp = hass.states.get(outdoor_temp_sensor)
    indoor_hum = hass.states.get(indoor_humidity_sensor)
    if indoor_temp:
        self._indoor_temp = MoldIndicator._update_temp_sensor(indoor_temp)
    if outdoor_temp:
        self._outdoor_temp = MoldIndicator._update_temp_sensor(outdoor_temp)
    if indoor_hum:
        self._indoor_hum = MoldIndicator._update_hum_sensor(indoor_hum)
