def shrink_pool(arg, opts, shell_opts):
    """ Shrink a pool by removing the ranges in opts from it
    """
    if not pool:
        print("No pool with name '%s' found." % arg, file=sys.stderr)
        sys.exit(1)

    if 'remove' in opts:
        res = Prefix.list({'prefix': opts['remove'], 'pool_id': pool.id})

        if len(res) == 0:
            print("Pool '%s' does not contain %s." % (pool.name,
                opts['remove']), file=sys.stderr)
            sys.exit(1)

        res[0].pool = None
        res[0].save()
        print("Prefix %s removed from pool '%s'." % (res[0].prefix, pool.name))
    else:
        print("Please supply a prefix to add or remove to '%s':" % (
            pool.name), file=sys.stderr)
        for pref in Prefix.list({'pool_id': pool.id}):
            print("  %s" % pref.prefix)
Shrink a pool by removing the ranges in opts from it