SAS PROC FCMP - Python Function (Resolving Error)

I need assistance with resolving the error while executing the attached code.

Step1:
I created first SAS dataset

SCENARIO.sas7bat
this dataset has two records ONLY.. base and severe

Step2:
I created two more datasets ending wit the record names
pre_proj_base.sas7bdat
pre_proj_severe.sas7bdat

Step3:
I created a new field in the above two datasets using a calculation logic

Step4:
I appended both the datasets to create final dataset
PRE_PROJ_ALL_SCN.sas7bdat

I have attached the code for reference.

When I execute the code in SAS environment, I am getting the following error
Unable to call function 'process scenarios'. Possible missing 'Output:' return signature in python source code.

Please resolve the error.

I am using SAS M7 version.