Hi, I thought it would be a good idea to have the option to have an array automatically add an _id field with new ObjectId per element if its an array of object. In our use cases, we mostly update/delete items by their _id. In the case where we want to do a bulk $push or something similar, there are currently no way of generating the _id's except looping through our array and generating the ids beforehand which is not ideal. Another option would be to be able to use an update operator to generate a new ObjectId. For example: ``` updateMany({},{ $push: { "myArray": { someField: "someValue", _id: "$ObjectId" // this would generate a unique object id per element that is inserted in this update operation. } } }); ```