minor fix
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index 2643883..de92f13 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -342,6 +342,8 @@
 
 @frappe.whitelist()
 def get_taxes_and_charges(master_doctype, master_name):
+	if not master_name:
+		return
 	from frappe.model import default_fields
 	tax_master = frappe.get_doc(master_doctype, master_name)