'Represents an update_one operation.
For use with :meth:`~pymongo.collection.Collection.bulk_write`.
:Parameters:
- `filter`: A query that matches the document to update.
- `update`: The modifications to apply.
- `upsert` (optional): If ``True``, perform an insert if no documents
match the filter.
- `collation` (optional): An instance of
:class:`~pymongo.collation.Collation`. This option is only
supported on MongoDB 3.4 and above.
.. versionchanged:: 3.5
Added the `collation` option.'

def __init__(self, filter, update, upsert=False, collation=None):

    super(UpdateOne, self).__init__(filter, update, upsert, collation)
