where has gr.feval_dd gone?

I'm trying to run some ~4 year old python code based on the even older usrp_spectrum_sense.py example.

This line 

class tune(gr.feval_dd):

triggers AttributeError: module 'gnuradio.gr' has no attribute 'feval_dd'

Has this been deprecated? This is on a fresh anaconda install with gnuradio 3.10.9.2