Use absolute path instead of relative
In trytond, we have many relative import path. It works but they make maintenance more complicated and also it is harder to read (ex: from ...rpc import RPC).
I think we must use absolute path when the imported file is clearly from a different context. So relative import is still logical (and needed) in __init__.py but also for example inside the same folder like in trytond/model/fields between each fields.