Onion Omega with Adafruit Power Board 500 mA, shutting down the onion when battery is now or power disconnected

lowBatteryShutdown.py

import sys, os, datetime
from gpiohelper import GPIOHelper

helper = GPIOHelper()

vInPin = 12
lowBatteryPin = 8
pinToCheck = vInPin;

durationOfNotOKInMinutesBeforeShutdown = 1

# GPIO value interpretation is different for vIn and battery
pinToCheckOKValue = 1 if pinToCheck == vInPin else 0;
vInInitialValue = helper.getPin(vInPin)
pinToCheckLastValue = 1 if vInInitialValue else 0

# this check is to ensure the system is not shutdown by this script when onion was powered on in battery mode
if pinToCheck != vInPin or vInInitialValue:
    while True:
        if helper.getPin(pinToCheck) != pinToCheckOKValue and helper.getPin(pinToCheck) != pinToCheckLastValue:
            print "lowBatteryShutdown: Power Source failure. Shutdown in {} minutes.".format(durationOfNotOKInMinutesBeforeShutdown)
        elif helper.getPin(pinToCheck) != pinToCheckOKValue:
            if lastOKTime + datetime.timedelta(minutes=durationOfNotOKInMinutesBeforeShutdown) < datetime.datetime.utcnow() and helper.getPin(pinToCheck) != pinToCheckLastValue:
                print "lowBatteryShutdown: Shutdown system now."
                os.system("halt -f")
        elif helper.getPin(pinToCheck) == pinToCheckOKValue and helper.getPin(pinToCheck) != pinToCheckLastValue:
            print "lowBatteryShutdown: Power Source recovered."
        else:
            lastOKTime = datetime.datetime.utcnow()

        pinToCheckLastValue = helper.getPin(pinToCheck)
        sys.stdout.flush()