Update shipment.py
diff --git a/erpnext/stock/doctype/shipment/shipment.py b/erpnext/stock/doctype/shipment/shipment.py
index 9167bfc..4697a7b 100644
--- a/erpnext/stock/doctype/shipment/shipment.py
+++ b/erpnext/stock/doctype/shipment/shipment.py
@@ -5,7 +5,7 @@
 from __future__ import unicode_literals
 import frappe
 from frappe import _
-from frappe.utils import flt, get_time, to_timedelta
+from frappe.utils import flt, get_time
 from frappe.model.document import Document
 from erpnext.accounts.party import get_party_shipping_address
 from frappe.contacts.doctype.contact.contact import get_default_contact