code: def token_getter(remote, token=''):
      
      session_key = token_session_key(remote.name)
  
      if session_key not in session and current_user.is_authenticated:
          # Fetch key from token store if user is authenticated, and the key
          # isn't already cached in the session.
          remote_token = RemoteToken.get(
              current_user.get_id(),
              remote.consumer_key,
              token_type=token,
          )
  
          if remote_token is None:
              return None
  
          # Store token and secret in session
          session[session_key] = remote_token.token()
  
      return session.get(session_key, None)
docs: Retrieve OAuth access token.
  
      Used by flask-oauthlib to get the access token when making requests.
  
      :param remote: The remote application.
      :param token: Type of token to get. Data passed from ``oauth.request()`` to
          identify which token to retrieve. (Default: ``''``)
      :returns: The token.