Is it possible to specify a collation on a `find` / `find_one` query: ( [Ref](https://docs.mongodb.com/manual/reference/method/cursor.collation/) & [PyMongo](http://api.mongodb.com/python/current/examples/collations.html) ) with txmongo ? That can be used along with a [Case Insensitive Index](https://docs.mongodb.com/manual/core/index-case-insensitive/) to do a case-insensitive search without regexps