Improve methods order

[GabyUnalaq]

Description

The methods of a class should follow an ordering convention. Currently, all the methods are placed by either their usecase or just randomly in the class. The order should be like this:

1. Class-level attributes
2. init()
3. Magic methods like str, len, ...
4. Public instance methods
5. private or protected methods
6. static and class methods
7. cleanup (del)

Comment that mentioned this: #43 (comment)

Goals

The code is refactored and the methods are in a proper order.

Final result

Summary

To be filled when the final solution is sketched.

Tasks

• Reorder the methods in the sdk
• Optional: Reorder the unit test methods to match the implementation