__str__ fuction

backend/product/models.py

@@ -411,6 +411,9 @@ class ProductVariant(DirtyFieldsMixin, models.Model):
     created_at = models.DateTimeField(
         auto_now_add=True, verbose_name='زمان ثبت محصول')
     
+    def __str__(self):
+        return f"{self.product.name} - {', '.join(str(attr) for attr in self.product_attributes.all())}"
+
     class Meta:
         verbose_name = 'تنوع محصول'
         verbose_name_plural = 'تنوع‌های محصول'
@@ -433,8 +436,6 @@ class ProductVariant(DirtyFieldsMixin, models.Model):
                          name='variant_product_discount_idx'),
         ]
 
-    def __str__(self):
-        return f"{self.product.name} - {', '.join(str(attr) for attr in self.product_attributes.all())}"
 
     @property
     def price_before_discount(self):