How to handle unused imports?

[BenediktBurger]

Quite a few modules contain several imports which are not used.
Most linters complain about unused imports as they can have a negative impact.

It is best practice to not import something from a file, where it is imported as well, but directly from the source.
I understand, that it is sometimes useful.

Currently, some module import via some other module, therefore a developer never knows, when he can remove an import or not.

Could we have a clear policy how to handle imports?
For example:

• Standard lib imports are always direct, so an unused import from standard lib can be removed safely.
• All imports, which are required by another module have to be marked with a comment.