There is a coding typo found in the Using the DHT11 sensor lesson.
instance = dht11.DHT11(jpin=4) <-- typo
GPIO.setwarnings(True)
GPIO.setmode(GPIO.BCM)
Needs to be changed to:
instance = dht11.DHT11(pin=4)
GPIO.setwarnings(True)
GPIO.setmode(GPIO.BCM)