quickstart.py

from __future__ import print_function
import httplib2
import os
from apiclient.discovery import build
from httplib2 import Http
from oauth2client import file, client, tools

# Setup the Gmail API
SCOPES = 'https://www.googleapis.com/auth/gmail.readonly'
store = file.Storage('credentials.json')
creds = store.get()
if not creds or creds.invalid:
    flow = client.flow_from_clientsecrets('client_secret.json', SCOPES)
    creds = tools.run_flow(flow, store)
service = build('gmail', 'v1', http=creds.authorize(Http()))

# Call the Gmail API
results = service.users().labels().list(userId='me').execute()
labels = results.get('labels', [])
if not labels:
    print('No labels found.')
else:
    print('Labels:')
    for label in labels:
        print(label['name'])