function wpf_add_note_to_nationbuilder( $entry, $form ) {

    if ( ! function_exists( 'wp_fusion' ) ) {
        return;
    }

    $contact_id = gform_get_meta( $entry['id'], 'wpf_contact_id' );

    if ( ! empty( $contact_id ) ) {

        $params = wp_fusion()->crm->get_params();

        $body = array(
            'note' => array(
                'content' => $entry['4'],
            ),
        );

        $params['body'] = json_encode( $body );

        $request  = 'https://' . wp_fusion()->crm->url_slug . '.nationbuilder.com/api/v1/people/' . $contact_id . '/notes/?access_token=' . wp_fusion()->crm->token;
        $response = wp_remote_post( $request, $params );

    }

}

add_action( 'gform_after_submission', 'wpf_add_note_to_nationbuilder', 10, 2 );