This simple gist demonstrates the use of third-party QR Code packages with Python3 to generate and decode QR Codes and Bar Codes alike!

QRCodeGenerationAndDecoding.py

###Generating a QR Code###
#pip install pyqrcode
#`pip install pypng` for PNG import errors, or try reinstalling Pillow!


import pyqrcode 
from PIL import Image
s = "www.geeksforgeeks.org" 
url = pyqrcode.create(s) 

#url.svg("myqr.svg", scale = 8) 
url.png("code.png", scale=8) #Creates QR code PNG image in the current working directory!


###Decoding a QR Code##
#pip install pyzbar
#pip install pillow

from pyzbar.pyzbar import decode as qr_decode
from PIL import Image

data = qr_decode(Image.open('code.png'))
# To get the data
print(data)
# To get the message
print(data[0][0].decode('utf-8'))