I have some data that I needed to sift through. I ended up using `$facet` to find the data, perform some calculations, and then combine the results using `$concatArrays`.
My query looks something like this:

```
db.myColl.aggregate([
   {...},
   {...},
  {$facet:{res1:[...],res2:[...],...}},
  {$project:{"result": {$concatArrays:[res1, res2, res3, ...]}}}
  ])

```

and I get the output below:

```
{"results":[{"_id":0,"data":"1"},{"_id":1,"data":"2"},{"_id":2,"data":"3"}]}

```

However, I want to then iterate over the results of the query in python and would prefer the data to look like below

```
{"_id":0,"data":"1"}
{"_id":1,"data":"2"}
{"_id":2,"data":"3"}

```

This more closely resembles the output of a `$match` query. To my understanding `$match` returns a collection of documents rather than an array of elements.

How can I coax my pipeline to get the output to look like this? Ideally the change in my pipeline would be modifying the final `$project` stage or adding additional stages to my pipeline.

**What I've tried so far**

I've tried adding `{$replaceRoot:{newRoot:"$results"}` to the pipeline but I get an error because it does not accept arrays.

I've also tried adding `{$project: {_id:"$results._id",data:"$results.data"}`
but this gives me 

```
{
  "_id":[0,1,2],
  "data":[1,2,3]
}

```