<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_item(track_url, client_id=CLIENT_ID):
 """ Fetches metadata for a track or playlist """

    try:
        item_url = url['resolve'].format(track_url)

        r = requests.get(item_url, params={'client_id': client_id})
        logger.debug(r.url)
        if r.status_code == 403:
            return get_item(track_url, ALT_CLIENT_ID)

        item = r.json()
        no_tracks = item['kind'] == 'playlist' and not item['tracks']
        if no_tracks and client_id != ALT_CLIENT_ID:
            return get_item(track_url, ALT_CLIENT_ID)
    except Exception:
        if client_id == ALT_CLIENT_ID:
            logger.error('Failed to get item...')
            return
        logger.error('Error resolving url, retrying...')
        time.sleep(5)
        try:
            return get_item(track_url, ALT_CLIENT_ID)
        except Exception as e:
            logger.error('Could not resolve url {0}'.format(track_url))
            logger.exception(e)
            sys.exit(0)
    return item