Cannot unpack noniterable bool object

Question

I'm new to Python and posting on SO.

I'm doing a class project on trying to create an automated climate control system with a Raspberry pi(Pi4 4GB) and a DHT. Here is my current error and code and I'm not sure what's causing the fail in the loop. It works for a while then errors out. It seems to error when it gets a bad read from the sensor, but until then it works fine.

Traceback (most recent call last):
  File "/home/pi/raphael-kit/python/Climatecontrol.py", line 156, in <module>
    main()
  File "/home/pi/raphael-kit/python/Climatecontrol.py", line 118, in main
    humidity, temperature = readDht11()
TypeError: cannot unpack non-iterable bool object

import RPi.GPIO as GPIO
import time
import LCD1602

dhtPin = 17
relayPin = 23 # Set GPIO23 as control pin
set_temp = 25  # this is the required temperature
GPIO.setmode(GPIO.BCM)
# Set relayPin's mode to output,
# and initial level to High(3.3v)
GPIO.setup(relayPin, GPIO.OUT, initial=GPIO.HIGH)




MAX_UNCHANGE_COUNT = 100

STATE_INIT_PULL_DOWN = 1
STATE_INIT_PULL_UP = 2
STATE_DATA_FIRST_PULL_DOWN = 3
STATE_DATA_PULL_UP = 4
STATE_DATA_PULL_DOWN = 5

def readDht11():
    GPIO.setup(dhtPin, GPIO.OUT)
    GPIO.output(dhtPin, GPIO.HIGH)
    time.sleep(0.05)
    GPIO.output(dhtPin, GPIO.LOW)
    time.sleep(0.02)
    GPIO.setup(dhtPin, GPIO.IN, GPIO.PUD_UP)

    unchanged_count = 0
    last = -1
    data = []
    while True:
        current = GPIO.input(dhtPin)
        data.append(current)
        if last != current:
            unchanged_count = 0
            last = current
        else:
            unchanged_count += 1
            if unchanged_count > MAX_UNCHANGE_COUNT:
                break

    state = STATE_INIT_PULL_DOWN

    lengths = []
    current_length = 0

    for current in data:
        current_length += 1

        if state == STATE_INIT_PULL_DOWN:
            if current == GPIO.LOW:
                state = STATE_INIT_PULL_UP
            else:
                continue
        if state == STATE_INIT_PULL_UP:
            if current == GPIO.HIGH:
                state = STATE_DATA_FIRST_PULL_DOWN
            else:
                continue
        if state == STATE_DATA_FIRST_PULL_DOWN:
            if current == GPIO.LOW:
                state = STATE_DATA_PULL_UP
            else:
                continue
        if state == STATE_DATA_PULL_UP:
            if current == GPIO.HIGH:
                current_length = 0
                state = STATE_DATA_PULL_DOWN
            else:
                continue
        if state == STATE_DATA_PULL_DOWN:
            if current == GPIO.LOW:
                lengths.append(current_length)
                state = STATE_DATA_PULL_UP
            else:
                continue
    if len(lengths) != 40:
        #print ("Data not good, skip")
        return False

    shortest_pull_up = min(lengths)
    longest_pull_up = max(lengths)
    halfway = (longest_pull_up + shortest_pull_up) / 2
    bits = []
    the_bytes = []
    byte = 0

    for length in lengths:
        bit = 0
        if length > halfway:
            bit = 1
        bits.append(bit)
    #print ("bits: %s, length: %d" % (bits, len(bits)))
    for i in range(0, len(bits)):
        byte = byte << 1
        if (bits[i]):
            byte = byte | 1
        else:
            byte = byte | 0
        if ((i + 1) % 8 == 0):
            the_bytes.append(byte)
            byte = 0
    #print (the_bytes)
    checksum = (the_bytes[0] + the_bytes[1] + the_bytes[2] + the_bytes[3]) & 0xFF
    #if the_bytes[4] != checksum:
        #print ("Data not good, skip")
        #return False

    return the_bytes[0], the_bytes[2]

def main():

    while True:
        humidity, temperature = readDht11()

        if humidity is not None and temperature is not None:
            print("Temp={0:0.1f}*C  Humidity={1:0.1f}%".format(temperature, humidity))
    
            # test for low temperature
            if temperature < set_temp:
                print(GPIO.output(relayPin, GPIO.LOW))
            
            # test for high temperature
            if temperature > (set_temp + 1):
                print(GPIO.output(relayPin, GPIO.HIGH))    
    
    else:
        print("Failed to retrieve data from humidity sensor")
        
    time.sleep(5)  #this is the time between taking readings and acting on them you can reduce it but not below 5 seconds
# Define a destroy function for clean up everything after
# the script finished


def setup():
    LCD1602.init(0x27, 1)   # init(slave address, background light)
    LCD1602.write(0, 0, 'Temperature: %s C')
    LCD1602.write(1, 1, 'humidity: %s %%')
    time.sleep(2)
    
    
def destroy():
    # set relay to off 
    GPIO.output(relayPin, GPIO.LOW)
    # Release resource
    GPIO.cleanup()



if __name__ == '__main__':
    try:
        setup()
    except KeyboardInterrupt:
        destroy()

as a note I haven't managed to get the LCD working in tandem but im more worried about the main functionality