[IMP] l10n_it_delivery_note: avoid error when invoicing delivery notes filtered by multiple partners

Author: Borruso

l10n_it_delivery_note/wizard/delivery_note_invoice.py

@@ -50,13 +50,13 @@ def create_invoices(self):
         delivery_note_ids = self.env["stock.delivery.note"].browse(
             self._context.get("active_ids", [])
         )
-        if len(delivery_note_ids.mapped("partner_id")) > 1:
-            raise UserError(
-                self.env._("You must select only delivery notes from one partner.")
+        for partner in delivery_note_ids.mapped("partner_id"):
+            dns_partner = delivery_note_ids.filtered(
+                lambda dn, p=partner: dn.partner_id == p
+            )
+            dns_partner.action_invoice(
+                invoice_method=self.invoice_method, final=self.deduct_down_payments
             )
-        delivery_note_ids.action_invoice(
-            invoice_method=self.invoice_method, final=self.deduct_down_payments
-        )
         invoices_ids = delivery_note_ids.mapped("invoice_ids")
         if not invoices_ids:
             raise UserError(