Merge pull request #16451 from nabinhait/unicode-issue

fix: Unicode issue in purchase invoice
diff --git a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
index d28dc93..f2d5006 100644
--- a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
+++ b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
@@ -1,7 +1,8 @@
 # Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 # License: GNU General Public License v3. See license.txt
+# -*- coding: utf-8 -*-
 
-
+from __future__ import unicode_literals
 import frappe, erpnext
 from frappe.utils import cint, cstr, formatdate, flt, getdate, nowdate
 from frappe import _, throw