Add typehints

[LordGvozd]

Description

Currently, the project code does not use type annotations, which can make it difficult to understand data types and complicate code maintenance and refactoring.

Proposal

I propose to gradually add type annotations to the project.

Why is this important?

Adding type annotations will improve code readability, which will simplify code support and adding new features. Also a static analyzer of mypy type may reduce the number of bugs.

[LordGvozd]

@Mr-Sunglasses What do you think about it? Can I work on this?

[Mr-Sunglasses]

@Mr-Sunglasses What do you think about it? Can I work on this?

Thanks @LordGvozd , go ahead, I've assigned the issue to you.

[LordGvozd]

Thanks! Can I upgrade python version?