The python-quickbooks library is probably the correct choice now, as it is a "complete rework of quickbooks-python". It has pretty comprehensive instructions on getting and using the auth keys, though I wouldn't call it "simple", since the process is by definition somewhat complex. The instructions are "for Django", but the Django-specific code simply gets parameters out of a URL string.
We're using it to great effect, because the syntax is as easy as:
auth_client = AuthClient(
client_id = CLIENT_ID # from QB website
,client_secret = CLIENT_SECRET # from QB website
,environment = 'sandbox' # or 'production'
,redirect_uri = REDIRECT_URI
)
client = QuickBooks(
auth_client = auth_client
,refresh_token = REFRESH_TOKEN
,company_id = COMPANY_ID
)
account = Account.get(qbid, qb=client) # qbid can be retrieved from the AccountList
return account.CurrentBalance