Since v14, Odoo defines the `__slots__` attribute in the `BaseModel` class (ea3e39506a)
This makes it impossible to add attributes to an instance like it was done here in v13.
The use of the `report_data` dictionary passed between method is the closes and simples solution to this "issue".
TT26415
Co-authored-by: Alex Cuellar <acuellar@grupoyacck.com>
João Marques