Clean-up callbacks for non-SR functions

Greets,

Is there a way for me to clean up fn_extra in flinfo when the function is not
a Set Returning Function(SRF)?

I know I can use RegisterExprContextCallback and the RSI's econtext to register a callback
for SRFs, but this--or similar functionality--does not appear to be available for non-SRFs.

Am I missing something?

(This question comes from trying to keep non-SRF generator support in PL/Py
from leaking all over the floor..)

Regards,       James William Pye