checkpoint_4a.py

import webiopi
from webiopi.devices.digital import PCF8574A
mcp = PCF8574A(slave=0x38)

GPIO = webiopi.GPIO # Assign webiopi library to GPIO object

LED0 = 0 # Set PCF8574 GPIO pin 0 to connect to the LED (negative logic)

mcp.setFunction(LED0, GPIO.OUT) #Set Pin 0 as output
mcp.digitalWrite(LED0, GPIO.LOW) # Turn on the LED for the first time

"""
   Function to toggle logic
"""
def toggleLED0():
  while True: # Always run loop
    value = not mcp.digitalRead(LED0)  # Assign opposite of current state (i.e. high or low) to value 
    mcp.digitalWrite(LED0, value) # Write assigned value to GPIO
    webiopi.sleep(0.10) # Wait 2 seconds
toggleLED0() # Call toggle function.