def _update_compressed(
        collection_name, upsert, multi, spec, doc, check_keys, opts, ctx):
    """Internal compressed unacknowledged update message helper."""
    op_update, max_bson_size = _update(
        collection_name, upsert, multi, spec, doc, check_keys, opts)
    rid, msg = _compress(2001, op_update, ctx)
    return rid, msg, max_bson_size
Internal compressed unacknowledged update message helper.
stackoverflow/venv/lib/python3.6/site-packages/pymongo/message.py