📋 Overview

This pull request implements a comprehensive standardisation of type hints across the entire codebase, transitioning from custom type aliases to standard Python typing constructs. By leveraging collections.abc.Collection and explicit generic types like list[str], the project achieves better compatibility with modern static analysis tools and improves overall code clarity. Additionally, this PR simplifies complex function overloads, relocates constants to more appropriate modules, and enhances documentation for core classes.

🛠️ Type Hint and Import Standardisation

Transition to Standard Library Types

• checkers.py: Replace custom any_collection and str_collection aliases with Collection[Any] and Collection[str] to align with standard Python protocols
• bools.py: Update strtobool() to use list[str] for internal truthy and falsy value tracking
• collection_types.py: Remove redundant type aliases and relocate the log_levels literal to the output.py module where it is primarily utilised
• defaults.py: Standardise the __all__ export list and internal validation lists to use the native list[str] type
• dictionaries.py: Refactor dict_reverse_keys_and_values() to use explicit dict[Any, Any] and dict[str, Any] type hints
• lists.py: Update flatten() and flat_list() to return standard list[Any] instead of custom list aliases
• strings.py: Replace str_list_tuple with Union[list[str], tuple[str, ...]] in string membership functions for better transparency

Dependency Cleanup

• Imports: Remove numerous imports from toolbox_python.collection_types across all modules, reducing internal coupling and simplifying the dependency graph
• Aliases: Add explicit Callable[..., bool] and Callable[..., None] type annotations to function aliases in checkers.py to ensure they are correctly recognised by type checkers

⚙️ Function Logic and Overload Simplification

Streamlined Type Checking

• is_value_of_type(): Simplify the function signature by using Union[type, Collection[type]], allowing for a more robust handling of both single types and collections of types
• is_all_values_of_type(): Reduce the number of @overload definitions by consolidating input types into Collection[Any] and Collection[type]
• assert_value_of_type(): Refactor assertion logic to match the simplified checking patterns, ensuring consistent behaviour across the validation suite
• Internal Logic: Improve the conversion of check_type to a tuple by using a more direct not isinstance(check_type, type) check, which correctly handles all non-type iterables

Enhanced Output and List Utilities

• list_columns(): Remove redundant @overload declarations and use Literal[True, False] for the print_output parameter to provide clearer intent to the caller
• flatten(): Refine the input type to Collection[Collection[Any]] to more accurately represent the expected nested structure and remove unnecessary type: ignore comments

📖 Documentation and Metadata Improvements

Class and Method Documentation

• Defaults(): Update the class docstring to include a dedicated "Methods" section, explicitly documenting the .get(), ._validate_value_and_default(), and ._validate_type() methods
• retry(): Add descriptive docstrings for the _exceptions type alias and the R TypeVar to improve maintainability of the retry logic
• Docstring Accuracy: Update parameter descriptions in multiple functions to reflect the shift from "tuple of types" to the more general "Sequence of types" or "Collection of types"

Module Exports

• __all__: Ensure all modules have their __all__ lists correctly typed as list[str] and include newly relocated constants like log_levels in output.py