adding or updating of fields in mongodb
update_many(filter, update, upsert=False, array_filters=None, bypass_document_validation=False, collation=None, session=None)
filter: A query that matches the documents to update.
update: The modifications to apply.
upsert (optional): If True, perform an insert if no documents match the filter.
bypass_document_validation (optional): If True, allows the write to opt-out of document level validation. Default is False.
collation (optional): An instance of Collation. This option is only supported on MongoDB 3.4 and above.
array_filters (optional): A list of filters specifying which array elements an update should apply. Requires MongoDB 3.6+.
session (optional): a ClientSession.