mongodb duplicates record delete

db.TEST.aggregate( [
{
$group: {
_id: "$FORMNUMBER",
count: { $sum: 1 }
}
},
{ $match: { count: { $gt: 1 } } }
]).forEach(
function(obj)
{
var cur = db.TEST.find({FORMNUMBER:obj._id }
);
var first = true;
while (cur.hasNext()) {
var doc = cur.next();
if (first)
{
first = false; continue;
}
db.TEST.remove({_id:doc._id });
}
});