code: def run(command, parser, cl_args, unknown_args):
    
    try:
      clusters = tracker_access.get_clusters()
    except:
      Log.error("Fail to connect to tracker: \'%s\'", cl_args["tracker_url"])
      return False
    print('Available clusters:')
    for cluster in clusters:
      print('  %s' % cluster)
    return True
docs: run command