python - insert not duplicate data with Pymongo in mongodb -

now,i try insert data pymongo in mongoldb.

get_db().users.update({'_id':objectid(session['user_id'])},{'$push':{'hme':objectid(id)}},upsert=true) 

but,the method produce duplicate objectid.before try find_one().

if not objectid(id) in get_db().users.find_one({'_id':objectid(session['user_id'])})['hme']:     get_db().users.update({'_id':objectid(session['user_id'])},{'$push':{'hme':objectid(id)}},upsert=true) 

better method request..

may use foreach.but syntax error

yang

if hme key holds arrays of objectids try $addtoset operator instead of $push since adds value array unless value present, in case $addtoset nothing array ensures there no duplicate items added set , not affect existing duplicate elements:

get_db().users.update(    {'_id':objectid(session['user_id'])},    {        '$addtoset':{            'hme':objectid(id)        }    },    upsert=true )