text: import os
  
  from googleapiclient import discovery
  import httplib2
  from oauth2client import client, tools
  from oauth2client.file import Storage
  
  try:
  	import argparse
  	flags = argparse.ArgumentParser(parents=[tools.argparser]).parse_args()
  except ImportError:
  	flags = None
  
  # If modifying these scopes, delete your previously saved credentials
  # at ~/.credentials/calendar-python-quickstart.json
  SCOPES = 'https://www.googleapis.com/auth/calendar.readonly'
  CLIENT_SECRET_FILE = 'client_secret.json'
  APPLICATION_NAME = 'Google Calendar API Python Quickstart'
  
  def get_credentials():
  	"""Gets valid user credentials from storage.
  
  	If nothing has been stored, or if the stored credentials are invalid,
  	the OAuth2 flow is completed to obtain the new credentials.
  
  	Returns:
  		Credentials, the obtained credential.
  	"""
  	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
  
  def get_service():
  	credentials = get_credentials()
  	http = credentials.authorize(httplib2.Http())
  	service = discovery.build('calendar', 'v3', http=http)
  	return service
  
  