Remove setters and getters

[adrienhenry]

What would you like ?
Fix the getter and setters in the lib

Why is this needed ?
To comply with the wemake-python-styleguide WPS 615 that forbids setter and getters:

https://wemake-python-styleguide.readthedocs.io/en/latest/pages/usage/violations/oop.html#wemake_python_styleguide.violations.oop.UnpythonicGetterSetterViolation

[adrienhenry]

For now I ignore theWPS615 check