PsychoPy won't run DARC toolbox

I had some delay discounting tasks using the DARC toolbox - same format as the Demos [adaptiveDecisionMaking, adaptiveHyperbolicDiscounting] - that were working fine up until about 1 month ago.

Now every time I try to run the tasks I get the following error message:

design_thing = BayesianAdaptiveDesignGeneratorDARC(D, max_trials=expInfo[‘trials’])
TypeError: Can’t instantiate abstract class BayesianAdaptiveDesignGeneratorDARC with abstract methods add_design_response_to_dataframe, df_to_design_tuple
################ Experiment ended with exit code 1 [pid:24052] #################

I get the same message when attempting to run the demos.

Has anyone else encountered this?

Any help would be greatly appreciated.