Improve exception handling in model loading

[felixkamau]

This pull request enhances the exception handling in the code responsible for loading data from 'saved_steps.pkl'. The improvements include the use of specific exception types for better error diagnosis and more informative error messages. Additionally, optional raise statements have been added to propagate exceptions for further analysis if desired.

Changes Made

• Used specific exception types (FileNotFoundError, pickle.PickleError, KeyError) for targeted error handling.
• Provided more informative error messages to guide users in case of a FileNotFoundError or specific issues during data loading.
• Optionally added raise statements to propagate exceptions for better debugging if needed.

Testing

The changes have been tested with both existing and non-existing 'saved_steps.pkl' files to ensure appropriate handling of different scenarios.