does not work because split returns a list of strings. However, the output schema is known, and it would be quite simple to implicitly promote the string element to a tupled element.
also, a list/array/tuple/set etc. are all equally convertable to bag, and list/array/tuple are equally convertable to Tuple, this conversion can be done in a much less rigid way with the use of the schema.
this allows much more facile re-use of existing python code and less memory overhead to create intermediate re-converting of object types.
I have written the code to do this a while back as part of my version of the jython script framework, i'll isolate that and attach.