refactor: extract common validation method

erpnext/stock/doctype/delivery_note/delivery_note.py

@@ -361,32 +361,23 @@ def validate_references(self):
 		self.validate_sales_invoice_references()
 
 	def validate_sales_order_references(self):
-		errors = []
-		for item in self.items:
-			missing_label = None
-			if item.against_sales_order and not item.so_detail:
-				missing_label = item.meta.get_label("so_detail")
-			elif item.so_detail and not item.against_sales_order:
-				missing_label = item.meta.get_label("against_sales_order")
-
-			if missing_label and missing_label != "No Label":
-				errors.append(
-					_("The field {0} in row {1} is not set").format(
-						frappe.bold(_(missing_label)), frappe.bold(item.idx)
-					)
-				)
-
-		if errors:
-			frappe.throw("<br>".join(errors), title=_("References to Sales Orders are Incomplete"))
+		self._validate_dependent_item_fields(
+			"against_sales_order", "so_detail", _("References to Sales Orders are Incomplete")
+		)
 
 	def validate_sales_invoice_references(self):
+		self._validate_dependent_item_fields(
+			"against_sales_invoice", "si_detail", _("References to Sales Invoices are Incomplete")
+		)
+
+	def _validate_dependent_item_fields(self, field_a: str, field_b: str, error_title: str):
 		errors = []
 		for item in self.items:
 			missing_label = None
-			if item.against_sales_invoice and not item.si_detail:
-				missing_label = item.meta.get_label("si_detail")
-			elif item.si_detail and not item.against_sales_invoice:
-				missing_label = item.meta.get_label("against_sales_invoice")
+			if item.get(field_a) and not item.get(field_b):
+				missing_label = item.meta.get_label(field_b)
+			elif item.get(field_b) and not item.get(field_a):
+				missing_label = item.meta.get_label(field_a)
 
 			if missing_label and missing_label != "No Label":
 				errors.append(
@@ -396,7 +387,7 @@ def validate_sales_invoice_references(self):
 				)
 
 		if errors:
-			frappe.throw("<br>".join(errors), title=_("References to Sales Invoices are Incomplete"))
+			frappe.throw("<br>".join(errors), title=error_title)
 
 	def validate_proj_cust(self):
 		"""check for does customer belong to same project as entered.."""