SCOPES = 'https://www.googleapis.com/auth/calendar'
CLIENT_SECRET_FILE = 'client_id.json'
APPLICATION_NAME = 'Google Calendar API Python Quickstart'


def get_credentials():

home_dir = os.path.expanduser('~')
credential_dir = os.path.join(home_dir, '.credentials')
if not os.path.exists(credential_dir):
    os.makedirs(credential_dir)
credential_path = os.path.join(credential_dir,
                               'calendar-python-quickstart.json')

store = Storage(credential_path)
credentials = store.get()
if not credentials or credentials.invalid:
    flow = client.flow_from_clientsecrets(CLIENT_SECRET_FILE, SCOPES)
    flow.user_agent = APPLICATION_NAME
    if flags:
        credentials = tools.run_flow(flow, store, flags)
    else: # Needed only for compatibility with Python 2.6
        credentials = tools.run(flow, store)
    print('Storing credentials to ' + credential_path)
return credentials


credentials = get_credentials()
http = credentials.authorize(httplib2.Http())
service = discovery.build('calendar', 'v3', http=http)