Supplier pattern is not used to find best supplier
The variable it is intialized but not passed to find_best_supplier:
https://hg.tryton.org/modules/stock_supply/file/4eb621599293/purchase_request.py#l263
The variable it is intialized but not passed to find_best_supplier:
https://hg.tryton.org/modules/stock_supply/file/4eb621599293/purchase_request.py#l263