db.comment_object.aggregate([{
        $match: {
            $and: [{
                "beneficiaries": {
                    $exists: true
                }
            }, {
                "beneficiaries.0": {
                    $exists: true
                }
            }],
            "last_payout": {
                "$gte": "2018-03-01T00:00:00",
                "$lt": "2018-06-09T00:00:00"
            },
            "total_payout_value": {
                "$gte": 0.001
            }
        }
    },
    {
        $unwind: "$beneficiaries"
    }, {
        $group: {
            _id: "$beneficiaries.account",

            author_gbg: {
                $sum: "$total_payout_value"
            },
            beneficiary_gbg: {
                $sum: "$beneficiary_payout_value"
            },
            curator_gbg: {
                $sum: "$curator_payout_value"
            }
        }
    }
])