Type safety improvements

[myui]

This pull request focuses on improving code quality, addressing type safety, and enhancing maintainability across multiple files in the rtrec project. The changes include reordering imports for consistency, adding type annotations, fixing type-related issues, and improving error handling in specific methods.

Code Quality Improvements:

• Reordering Imports for Consistency:

  • Standardized the order of imports across several files, including movielens_dashboard.py, datasets.py, kaggle_datasets.py, and others. This helps maintain a consistent structure and readability. [1] [2] [3] [4]

• Type Annotations:

  • Added or refined type annotations in functions and methods to improve type safety. For example, added list[list[int]] in base.py and Dict[int, float] in hybrid.py. [1] [2] [3]

Type Safety Fixes:

• Type Ignore Comments:

  • Added # type: ignore comments in various places to suppress type-checking errors where necessary, such as in _recommend and partial_fit_items methods in slim_elastic.py and hybrid.py. [1] [2] [3]

• Assertions for Type Validation:

  • Introduced assertions to validate types at runtime, such as ensuring slim_ids and slim_scores are numpy arrays in _similar_items in hybrid.py.

Functional Enhancements:

• Error Handling:

  • Added error handling for edge cases, such as raising a ValueError when user_embeddings is None in _cold_user_features in hybrid.py.

• Matrix Type Validation:

  • Ensured that interaction matrices are in the correct sparse format (e.g., csc_matrix) before proceeding with operations in bulk_fit in hybrid.py.

These changes collectively improve the project's robustness, maintainability, and developer experience.

[Copilot]

Pull Request Overview

This PR enhances type safety, improves maintainability, and standardizes import ordering across the rtrec codebase. Key changes include:

• Reordered and deduplicated imports in utility, model, experiment, and example files.
• Added and refined type annotations, including Dict[int, float] and list[list[int]], and introduced # type: ignore where type-checker errors were suppressed.
• Improved runtime validations and error handling (e.g., raising ValueError for missing embeddings and enforcing csc_matrix types before bulk operations).

Reviewed Changes

Copilot reviewed 38 out of 38 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
rtrec/utils/identifiers.py	Removed stray blank import and fixed pass_through annotation placement
rtrec/utils/features.py	Reordered import of csr_matrix
rtrec/utils/diskcache.py	Added type annotation for lru_cache
rtrec/utils/collections.py	Annotated _key_to_index and _index_to_key
rtrec/tools/kinesis_consumer.py	Reordered and cleaned up imports
rtrec/serving/app.py	Consolidated imports and added logging
rtrec/recommender.py	Updated calls to generate_batches via class name
rtrec/models/slim.py	Removed unused imports and updated return signature calls
rtrec/models/lightfm.py	Renamed topk outputs for clarity
rtrec/models/internal/slim_elastic.py	Reordered imports; added # type: ignore annotations and matrix wrapper hints
rtrec/models/internal/lightfm_wrapper.py	Cleaned up import ordering
rtrec/models/hybrid.py	Annotated aggregation dicts; enforced CSC format; refined return types
rtrec/models/base.py	Clarified local variable naming and annotations
rtrec/models/init.py	Standardized export ordering
rtrec/experiments/utils.py	Moved pandas import to top
rtrec/experiments/split.py	Added typing imports for function annotations
rtrec/experiments/kaggle_datasets.py	Cleaned and reordered imports
rtrec/experiments/experiments.py	Consolidated model imports and annotated model
rtrec/experiments/datasets.py	Reordered imports for consistency
examples/streamlit/movielens/...	Reordered imports in dashboard example