Directly wrapping Python/Ruby/Perl functions in CWL

Apologies if this point is addressed elsewhere and I've missed a previous issue / listserv post. If there's a past discussion of this somewhere that addresses this, feel free to point me to where it has occurred.

In [DigDag](https://www.digdag.io/), it appears that you can directly use individual Python/Ruby functions as nodes in a workflow (see [here](http://docs.digdag.io/operators/scripting.html)). While this is currently possible in CWL by combining a Command Line Tool with a wrapper script using Python's argparse, it is a bit unwieldy / not as seamless as being able to directly specify in the workflow that you want to invoke a specific Python function. Are there any plans in the works to create a "Python Tool" or "Ruby Tool" specification for CWL so that end-users of CWL-based tools wouldn't need to go through the extra step of wrapping Python/Ruby functions with argparse?