LJ::set_interests — Change a user's interests.
LJ::set_interests(dbarg, u, old, new
dbarg. Deprecated; a master database handle ($dbh) or a master/slave set of database handles ($dbs).
u. A hashref of a row from the user table, sometimes called a "user object". Although only initially a row from the user table, gets a lot of tacked onto it from various other LJ API functions.
old. hashref of old interests (hashing being interest => intid)
new. listref of new interests