'''Module for sensor implementations'''
try:
    import Adafruit_DHT
except ImportError:
    raise ImportError('Adafruit_DHT library not found.')

def is_valid(temperature, humidity):
    '''Check if temperature and humidity are valid.'''
    return True if humidity <= 100.0 and humidity >= 0.0 and \
                   temperature <= 100.0 and temperature >= -50.0 else False

class Dht22(object):
    '''DHT 22 temperature and Humidity sensor class.'''
    sensor = 22
    pin = int()

    def __init__(self, pin):
        self.pin = pin

    def read(self):
        '''Read temperature and humidity.'''
        temperature = -200.0
        humidity = -1.0
        valid = False
        while valid is False:
            temperature, humidity = Adafruit_DHT.read_retry(self.sensor, self.pin)
            valid = is_valid(temperature, humidity)
        return temperature, humidity