'Initialize a new PM sensor.'

def __init__(self, mhz_client, sensor_type, temp_unit, name):

    self._mhz_client = mhz_client
    self._sensor_type = sensor_type
    self._temp_unit = temp_unit
    self._name = name
    self._unit_of_measurement = SENSOR_TYPES[sensor_type][1]
    self._ppm = None
    self._temperature = None
