def define_options(L_opts=[], L_brief=[], L_details=[], L_other=[]):
    """ Define several groupings with lists of show options. """
    L_opts = ['brief',
              'all',
              ]
    L_brief = ['computes',
               'servers',
               'server_groups',
               'migrations',
               'flavors',
               'images',
               ]
    L_details = ['computes',
                 'servers',
                 'server_groups',
                 'libvirt',
                 'migrations',
                 'flavors',
                 'images',
                 'volumes',
                 ]
    L_other = ['aggregates', 'topology', 'topology-long']
    return (L_opts, L_brief, L_details, L_other)