change: change logic in order/tasks/ file

core/apps/orders/tasks/order.py

@@ -1,17 +1,23 @@
 from celery import shared_task
+from django.db.models import F
 
 from core.apps.wherehouse.models.inventory import Inventory
 
 
 @shared_task
 def create_inventory(wherehouse, quantity, product, unity, price, project_folder, project, unity_price):
-      Inventory.objects.create(
-            wherehouse_id=wherehouse,
-            quantity=quantity,
+      inventory, created = Inventory.objects.get_or_create(
             product_id=product,
+            wherehouse_id=wherehouse,
             unity_id=unity,
+            defaults=dict(
+                  quantity=quantity,
                   price=price,
                   project_folder_id=project_folder,
                   project_id=project,
                   unit_price=unity_price
             )
+      )
+      if not created:
+        inventory.quantity = F('quantity') + quantity
+        inventory.save(update_fields=["quantity"])