The lines may or may not have a party depending on the account.
So the order key must avoid compare party instance with None value.
Closes#13268
(grafted from 97e730164485c038de7744ea0a3fb189fd7426fa)
--HG--
branch : 7.0
Replace the year of a date is not safe, it is better to use relativedelta.
Closes#13064
(grafted from 4b19fb0bc801a784139c0c6245d8649480e13280)
--HG--
branch : 7.0
When a new parent is added to a tree template like types, taxes or tax codes,
the corresponding record of the new template parent is not yet created.
So we need to use a default value for the parent and update again the tree
after creating the new records.
Closes#12755
(grafted from 561f9c7dbdc2a2c39c1fe5f6bf7274d01ee9ebd6)
--HG--
branch : 7.0
Cédric Krier