fix: convert age and education-num to numeric in load_preproc_data_adult

[aniruddhaadak80]

Summary

Fixes #421: load_preproc_data_adult fails with TypeError: unsupported operand type(s) for //: 'str' and 'int' when the age column is read as strings.

Root Cause

The custom_preprocessing function in data_preproc_functions.py applies arithmetic operations (//, <=, >=) directly on the age and education-num columns. When these columns are read as strings (e.g., due to CSV formatting with leading spaces), the operations fail.

Fix

Added pd.to_numeric() conversion for both age and education-num columns before applying arithmetic operations in the custom_preprocessing function of load_preproc_data_adult.

Files Changed

• aif360/algorithms/preprocessing/optim_preproc_helpers/data_preproc_functions.py: Added pd.to_numeric() calls for age and education-num columns

Testing

• Verified the fix resolves the TypeError when age/education-num columns contain string values
• Confirmed the output values are correct after conversion