What is the proper way of moving a number of records from one collection to another. I have come across several other SO posts such as [this](https://stackoverflow.com/a/41483981/6021490) which deal with achieve the same goal but none have a python implementation.

```
#Taking a number of records from one database and returning the cursor
cursor_excess_new = db.test_collection_new.find().sort([("_id", 1)]).limit(excess_num)

# db.test.insert_many(doc for doc in cursor_excess_new).inserted_ids

# Iterating cursor and Trying to write to another database
# for doc in cursor_excess_new:
#     db.test_collection_old.insert_one(doc)
result = db.test_collection_old.bulk_write([
    for doc in cursor_excess_new:
        InsertMany(doc for each doc in cur)
        pprint(doc)
])

```

If I use insert\_many, I get the following error: `pymongo.errors.OperationFailure: Writes to config servers must have batch size of 1, found 10`

bulk\_write is giving me a syntax error at the start of for loop.

What is the best practice and correct way of transferring records from one collection to another in pymongo so that it is atomic?