Python Authentication Errors

u'reason': u'Authentication Error', u'result': u'failure', u'oauth_error_message': u'oauth_problem=signature_invalid&debug_sbs=GET&http%3A%2F%2Fapi.shapeways.com%2Fmodel%2Fv1&oauth_consumer_key%xxxx%26oauth_nonce%xxxx%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1454880344%26oauth_token%xxxx%26oauth_version%3D1.0%26page%3D1'}
Traceback (most recent call last):
  File "GetListOfModels.py", line 25, in <module>
    q=t["models"]
KeyError: 'models'

# ******************************************************************************
# **
# ** BulkUploader.py - Bulk Upload Script for Shapeways.Com
# **
# ** You will need to visit the following page to get started as you need some
# ** Oauth stuff to get started.  There is a link on the first page that will
# ** take you to where you need to be to register an application:
# **
# **     https://developers.shapeways.com/getting-started?li=devhome_main
# **
# ** Once that is done update the below path statement to point to the directory
# ** where your models are stored...and where this program can find your
# ** Index.csv file that contains an inventory of your models with some 
# ** added details for the listings to be created.  The model title will be
# ** the model file name.  The index file has that name as the first column, 
# ** a numeric column that is currently not used but envisioned for markup,
# ** a model specific description that is appended to a stock description, and
# ** then a list of tags.
# **
# ** This is far from a finished piece of work...nor is it eloquent coding, 
# ** nor in fact does anything about the user interface make one smile!  What
# ** it does do, however, is provide a working example of an upload!
# **
# ** Run this script in a terminal window.  Go to your browser and enter
# ** localhost:3000/login.   You should be asked by Shapeways whether it is
# ** ok for your app to access your account.  Press the button and your upload
# ** should be processed.
# ******************************************************************************
import json
import base64
import os
import csv

from shapeways.client import Client

defaultPath = "/media/psf/Home/Desktop/models"

client = Client(
    consumer_key="YOUR GENERATED KEY HERE",
    consumer_secret="YOUR GENERATED SECRET HERE",
    callback_url="http://localhost:3000/callback")

def application(environ, start_response):
    url = environ["PATH_INFO"]
    if url.startswith("/favicon.ico"):
        start_response("204 No Content", [])
        return [""]
    elif url.startswith("/login"):
        url = client.connect()
        start_response("302 Found", [
            ("Location", str(url)),
        ])
        return [""]
    elif url.startswith("/callback"):
        client.verify_url(environ["QUERY_STRING"])
        start_response("302 Found", [
            ("Location", "http://localhost:3000/"),
        ])
        print "Going to uploadFiles"
        uF = str(uploadFiles())
        print "Back from uploadFiles"
        return (uF + " files Uploaded")
    else:
        start_response("200 Ok", [
            ("Content-Type", "application/json"),
        ])
        return ""

#
#   Drives the uploading of all files ending in .stl found on the default path
#   and in all of its subdirectories
#
def uploadFiles():
    fCount= 0
    for root, dirs, files in os.walk(defaultPath):
        print str(files)
        for file in files:
            if file.endswith(".stl"):
                print "Uploading " + file
                uploadFile(root, file)
                fCount += 1
    return(fCount)

#
#   Uploads an individual file found above
#
def uploadFile(root, file):
    #
    #   Find the model in our inventory index file
    #
    model = findModel(file)
    if model == "":
        print "NO match"
        return
    f = open(os.path.join(root, file), "r")

    #
    #   Create the payload expected by the API
    #
    payload = {
        "file": base64.b64encode(f.read()),
        "fileName": file,
        "hasRightsToModel": 1,
        "uploadScale": 0.001,
        "acceptTermsAndConditions": 1,
        "title": file,
        "description":  "This is a test: " + model["description"],
        "tags": model["tags"]
    }
    f.close()
    #
    #   Add the model
    #
    t=client.add_model(payload)

#
#   Load our inventory of model files from the csb index file.  Model file name
#   is the key, then download proce (who knew this was not an option!  Followed
#   by a field for additional description, and then a list of tags
#
def loadInventory():
    ifile  = open('Index.csv', "rb")
    reader = csv.reader(ifile)
    for row in reader:
        tags = []
        for i in range(3, len(row)):
            tags.append(row[i])        
        model = {"name" : row[0], "price" : row[1], "description":row[2], "tags": tags}
        temp = row[0].upper()
        models.update({temp: model})
    ifile.close()
    
#
#   Find the model file returning "" if not found
#
def findModel(model):
    try:
        return(models[model.upper()])
    except:
        return("")

#
#   Primary execution
#
if __name__ == "__main__":
    from wsgiref.simple_server import make_server
    models = {}
    loadInventory()
    try:
        httpd = make_server("", 3000, application)
        print "Tracking Server Listening on Port 3000"
        httpd.serve_forever()
    except KeyboardInterrupt:
        print "Exiting"

Drum.stl,1,"Something extra","Germany","Heavy"
Drum2.stl,1,"","Germany", "Medium"
Missing.stl,2,"","USA","Medium"
Drum4.stl,1,"One more extra thing","France"