Kotlin store Firebase query to use in helper function

So I have integrated Firestore into my android app and I am trying to create a helper function that handles the same repetitious addOnCompleteListener that would be needed for every db query that I need to store data with. I have this helper function working but right now it can only use the one query I pass into it. What I want to know is how should I store/pass to my helper function so that I can do a valid check in a when block? Here is what I am currently doing so you can understand how I am passing information around:

Sample query - db.collection("Users").document(user!!.uid).get()

user is a FirebaseUser

Calling helper function - utils.query(db.collection("Users").document(user!!.uid).get(), auth)

auth is a FirebaseAuth

query function:

fun query(query: Task<DocumentSnapshot>, auth: FirebaseAuth) {
    query.addOnCompleteListener { dbTask ->
        if (dbTask.isSuccessful) {
            val userDoc = dbTask.result
            if(userDoc != null) {
                if (userDoc.exists()) {
                    handleQuery(query, auth, true)
                } else {
                    handleQuery(query, auth)
                }
            }
        } else {
            Log.d("TAG", "Error: ", dbTask.exception)
        }
    }
}

handleQuery function:

private fun handleQuery(query: Task<DocumentSnapshot>, auth: FirebaseAuth, exists: Boolean = false) {
    val user = auth.currentUser
    when (query) {
        db.collection("Users").document(user!!.uid).get() -> {
            if (exists) Log.i("TAG", "User already exists.")
            else {
                Log.e("TAG", "User doesn't exist in db. Attempting to add...")
                db.collection("Users")
                    .document(user!!.uid)
                    .set(hashMapOf(
                        "uid" to user.uid,
                        "name" to user.displayName,
                        "email" to user.email,
                        "photoURL" to user.photoUrl
                    ))
                Log.i("TAG", "User has been added")
            }
        }
    }
}

Any help would be greatly appreciated.