Handle empty 'pred' lists gracefully in evaluate function

[mandlinsarah]

Description

Refactored the evaluate function to handle cases where the pred field in samples might be an empty list. This prevents indexing errors and ensures that the function can gracefully handle such edge cases without breaking.

Impact

• No core functionality is impacted.
• Improves stability and robustness of the evaluate function.

Detail

• Added conditional check to skip processing of samples with empty pred lists.