'Could not authenticate you.' when trying to update status

[newTwitDev]

I am trying to get a base example that will post a Tweet on behalf of a user. I have my app setup for read/write:

This application will be able to:
Read Tweets from your timeline.See who you follow, and follow new people.Update your profile.Post Tweets for you.

but it yields {u’errors’: [{u’message’: u’Could not authenticate you.’, u’code’: 32}]}

What am I missing here?

# -*- encoding: utf-8 -*-
from __future__ import unicode_literals
import requests
from requests_oauthlib import OAuth1
from urlparse import parse_qs

REQUEST_TOKEN_URL = "https://api.twitter.com/oauth/request_token"
AUTHORIZE_URL = "https://api.twitter.com/oauth/authorize?oauth_token="
ACCESS_TOKEN_URL = "https://api.twitter.com/oauth/access_token"

CONSUMER_KEY="direct from Appliucation settings of https://apps.twitter.com/app/#/keys"
CONSUMER_SECRET="direct from Appliucation settings of https://apps.twitter.com/app/#/keys"
OAUTH_TOKEN = ""
OAUTH_TOKEN_SECRET = ""


def setup_oauth():
    """Authorize your app via identifier."""
    # Request token
    oauth = OAuth1(CONSUMER_KEY, client_secret=CONSUMER_SECRET)
    r = requests.post(url=REQUEST_TOKEN_URL, auth=oauth)
    credentials = parse_qs(r.content)

    resource_owner_key = credentials.get('oauth_token')[0]
    resource_owner_secret = credentials.get('oauth_token_secret')[0]

    # Authorize
    authorize_url = AUTHORIZE_URL + resource_owner_key
    print 'Please go here and authorize: ' + authorize_url

    verifier = raw_input('Please input the verifier: ')
    oauth = OAuth1(CONSUMER_KEY,
                   client_secret=CONSUMER_SECRET,
                   resource_owner_key=resource_owner_key,
                   resource_owner_secret=resource_owner_secret,
                   verifier=verifier)

    # Finally, Obtain the Access Token
    r = requests.post(url=ACCESS_TOKEN_URL, auth=oauth)
    credentials = parse_qs(r.content)
    token = credentials.get('oauth_token')[0]
    secret = credentials.get('oauth_token_secret')[0]

    return token, secret


def get_oauth():
    oauth = OAuth1(CONSUMER_KEY,
                client_secret=CONSUMER_SECRET,
                resource_owner_key=OAUTH_TOKEN,
                resource_owner_secret=OAUTH_TOKEN_SECRET)
    return oauth

if __name__ == "__main__":
    if not OAUTH_TOKEN:
        token, secret = setup_oauth()
        print "OAUTH_TOKEN: " + token
        print "OAUTH_TOKEN_SECRET: " + secret
        oauth= OAuth1(CONSUMER_KEY,
                client_secret=CONSUMER_SECRET,
                resource_owner_key=token,
                resource_owner_secret=secret)
        screen_name='username'
        status="Hello World @%s!" % screen_name

        url='https://api.twitter.com/1.1/statuses/update.json?status='+status
        status="Hello World @%s!" % screen_name
        r = requests.get(url="https://api.twitter.com/1.1/statuses/mentions_timeline.json", auth=oauth)
        r = requests.post(url=url, auth=oauth)#, data=status)


        print r.json()

        print
    else:
        oauth = get_oauth()
        r = requests.get(url="https://api.twitter.com/1.1/statuses/mentions_timeline.json", auth=oauth)
        print r.json()

Note: if I revert to attempt to read the timeline, the return is just an empty JSON even though there is a test tweet on the account.

When prompted for the verifier, I am entering the oauth_verifier value.