code: 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
docs: 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.