def METHOD_NAME():
    """Attempt to login."""
    if not (
        'access_token_key' in session and
        'access_token_secret' in session
    ):
        raise NameError("No access keys")
    access_token = AccessToken(
        session['access_token_key'],
        session['access_token_secret']
    )
    session['username'] = handshaker.identify(access_token)['username']
    auth = OAuth1(
        client_key=consumer_token.key,
        client_secret=consumer_token.secret,
        resource_owner_key=access_token.key,
        resource_owner_secret=access_token.secret
    )
    return auth