Access the Alexa Shopping and To-Do Lists with Python3 request module

In a nutshell, I am attempting to access my Amazon account's default Shopping List and To-Do List via Python request module. I feel like there must be step that I am overlooking after attemtpint to follow the developer documentations on this topic. I went over the steps provided by the Alexa developer post Access the Alexa Shopping and To-Do Lists and here are small commentaries from my experience from the steps provided:

1. Configure permissions to access the Alexa lists in your skill.
   This step was rather simple. I started with creating my custom skill as advised here, but I ended up actually making the skill provided here, so essentially only completing the fist two steps. Once the custom skill was created, I was able to enable the read and write permissions for the Skill (toggled Lists Read/Write), thus giving the skill list access.
2. Design a user intent model that uses customer Alexa lists.
   This step I assume is skipped?? I did not see any reference to this step anywhere on the page besides the beginning.
3. Handling customer missing permissions.
   I just went to my Alexa App and enabled access inside the settings of my custom "Dev" skill in this stage.
4. Get access the customer's Alexa lists.
   Here I followed the steps for Out-of-session interaction and obtained "token". I believe this is Skill Messaging API Access Token?
5. Implement the list management capabilities in your skill service code.
   This, I suppose, is where my disconnect is shown. After acquiring my token, I attempt to use the List Management REST API. The following Python code attempts to list out my current lists that I have with my client ID and secret values loaded from a json file in the same directory:

import requests
import json

def main():
    # Load client ID and Secret values
    with open("client_info.json", "r") as cred:
        clientInfo = json.load(cred)

    clientID = clientInfo["clientID"]
    clientSecret = clientInfo["clientSecret"]


    # Gettign token for api requests

    HEADERS = {
        "X-Amzn-RequestId": "d917ceac-2245-11e2-a270-0bc161cb589d",

        "Content-Type": "application/json"
    }

    DATA = {"client_id": clientID, "grant_type": "client_credentials",
            "client_secret": clientSecret, "scope": "alexa:skill_messaging"}

    url = "https://api.amazon.com/auth/o2/token"

    DATA = json.dumps(DATA)
    response = requests.post(url, data=DATA, headers=HEADERS)
    print("Response for token: %s " % response)
    info = json.loads(response.text)
    token = info["access_token"]


    # seeing a list of all lists

    endpoint = "https://api.amazonalexa.com"
    url = endpoint + "/v2/householdlists/"

    HEADERS = {
        "Authorization": "Bearer " + token,
        "Content-Type": "application/json",
        "Accept": "application/json"
    }
    new_response = requests.get(url, headers=HEADERS)

    print("Response for list info: %s " % new_response)
    print(new_response.text)

if __name__ == "__main__":
    main()

The print statements show the following

Response for token: <Response [200]> 
Response for list info: <Response [403]> 
{"Message":"Not all permissions are authorized."}

I am not sure if this is possible, or if there is a step that I have overlooked. Any help is much appreciated!