I am no python expert but: Tutorial: Hello Analytics API
def get_results(service, profile_id):
# Use the Analytics Service Object to query the Core Reporting API
return service.data().ga().get(
ids='ga:' + profile_id,
start_date='2012-03-03',
end_date='2012-03-03',
metrics='ga:visits').execute()
The profile id has to start with a ga: so you should just be able to add your profile id there. You still need to be authenticated but you don't need to go though the Management API to get the profile information.
Oh and after spying on your old question: This should still work even though you are using a service account its the same your still authenticated. ( sorry for spying )
Hope this helps.