Find useless indexes on postres

gistfile1.sql

SELECT idstat.relname AS table_name, 
    indexrelname AS index_name, 
    idstat.idx_scan AS times_used,
pg_size_pretty(pg_relation_size(idstat.relname::regclass)) AS table_size,	pg_size_pretty(pg_relation_size(indexrelname::regclass)) AS index_size,
    n_tup_upd + n_tup_ins + n_tup_del as num_writes,
    indexdef AS definition
FROM pg_stat_user_indexes AS idstat JOIN pg_indexes ON indexrelname = indexname
    JOIN pg_stat_user_tables AS tabstat ON idstat.relname = tabstat.relname
WHERE idstat.idx_scan < 200
    AND indexdef !~* 'unique'
ORDER BY idstat.relname, indexrelname;