import sqlite3 def collate_reverse(string1, string2):    return -cmp(string1, string2) con = sqlite3.connect(":memory:")con.create_collation("reverse", collate_reverse) cur = con.cursor()cur.execute("create table test(x)")cur.executemany("insert into test(x) values (?)", [("a",), ("b",)])cur.execute("select x from test order by x collate reverse")for row in cur:    print rowcon.close()