Use beartype for runtime type checking

### 📝 Description of the feature

[Beartype](https://github.com/beartype/beartype) could be quite easily implemented as it is still the beginning of the project.

### 💡 Steps for implementing the feature

- [ ] Add [typing](https://docs.python.org/3/library/typing.html) through the code
- [ ] Use [beartype](https://github.com/beartype/beartype)

### 🔗 Useful links and references

_No response_

The issue names no files, entry points, or tests to start from. Review the repository’s Python code to identify where typing annotations and beartype would apply; done means the intended code is annotated and runtime type checking is used throughout the project.

Written by the indexing model from the issue text.