refactor: Folio no validation
diff --git a/erpnext/accounts/doctype/share_transfer/share_transfer.py b/erpnext/accounts/doctype/share_transfer/share_transfer.py
index 65f248e..d4aa0f0 100644
--- a/erpnext/accounts/doctype/share_transfer/share_transfer.py
+++ b/erpnext/accounts/doctype/share_transfer/share_transfer.py
@@ -168,10 +168,12 @@
 		return 'Outside'
 
 	def folio_no_validation(self):
-		shareholders = ['from_shareholder', 'to_shareholder']
-		shareholders = [shareholder for shareholder in shareholders if self.get(shareholder) is not '']
-		for shareholder in shareholders:
-			doc = self.get_shareholder_doc(self.get(shareholder))
+		shareholder_fields = ['from_shareholder', 'to_shareholder']
+		for shareholder_field in shareholder_fields:
+			shareholder_name = self.get(shareholder_field)
+			if not shareholder_name:
+				continue
+			doc = self.get_shareholder_doc(shareholder_name)
 			if doc.company != self.company:
 				frappe.throw(_('The shareholder does not belong to this company'))
 			if not doc.folio_no: